Quectel Wireless Solutions 201605M35 GSM/GPRS Module User Manual

Quectel Wireless Solutions Company Limited GSM/GPRS Module

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M35 User Manual
GSM/GPRS Module Series
Rev. M35_User_Manual_V3.1
Date: 2014-11-26
www.quectel.com
GSM/GPRS Module Series
M35 User Manual
Our aim is to provide customers with timely and comprehensive service. For any
assistance, please contact our company headquarters:
Quectel Wireless Solutions Co., Ltd.
Office 501, Building 13, No.99, Tianzhou Road, Shanghai, China, 200233
Tel: +86 21 5108 6236
Mail: info@quectel.com
Or our local office, for more information, please visit:
http://www.quectel.com/support/salesupport.aspx
For technical support, to report documentation errors, please visit:
http://www.quectel.com/support/techsupport.aspx
GENERAL NOTES
QUECTEL OFFERS THIS INFORMATION AS A SERVICE TO ITS CUSTOMERS. THE INFORMATION
PROVIDED IS BASED UPON CUSTOMERS’ REQUIREMENTS. QUECTEL MAKES EVERY EFFORT
TO ENSURE THE QUALITY OF THE INFORMATION IT MAKES AVAILABLE. QUECTEL DOES NOT
MAKE ANY WARRANTY AS TO THE INFORMATION CONTAINED HEREIN, AND DOES NOT ACCEPT
ANY LIABILITY FOR ANY INJURY, LOSS OR DAMAGE OF ANY KIND INCURRED BY USE OF OR
RELIANCE UPON THE INFORMATION. ALL INFORMATION SUPPLIED HEREIN IS SUBJECT TO
CHANGE WITHOUT PRIOR NOTICE.
COPYRIGHT
THIS INFORMATION CONTAINED HERE IS PROPRIETARY TECHNICAL INFORMATION OF
QUECTEL CO., LTD. TRANSMITTABLE, REPRODUCTION, DISSEMINATION AND EDITING OF THIS
DOCUMENT AS WELL AS UTILIZATION OF THIS CONTENTS ARE FORBIDDEN WITHOUT
PERMISSION. OFFENDERS WILL BE HELD LIABLE FOR PAYMENT OF DAMAGES. ALL RIGHTS ARE
RESERVED IN THE EVENT OF A PATENT GRANT OR REGISTRATION OF A UTILITY MODEL OR
DESIGN.
Copyright © Quectel Wireless Solutions Co., Ltd. 2015. All rights reserved.
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About the Document
History
Revision
Date
Author
Description
1.0
2011-12-29
Luka WU
Initial
1.
1.1
2012-05-18
2.
Luka WU
3.
4.
1.2
2012-09-19
1.
2.
3.
Luka WU
Added
current
consumption
in
GPRS
communication mode.
Modified AT command AT+QAUDCH in Chapter
3.10.
Modified the Footprint of recommendation.
Updated module package type.
4.
5.
Updated module functional diagram.
Updated Voltage ripple during transmitting.
Modified level match reference circuits for 5V
peripheral system.
Updated SIM card reference circuit.
Added module current consumption.
Updated information on module’s packaging.
Used the new technical document template.
1.3
2013-09-03
Winter CHEN
1.
2.
1.4
2013-11-04
Felix YIN
Optimized the parameters of VBAT ripple in Table 24.
1.
3.0
2014-07-25
Winter CHEN
2.
3.
4.
5.
1.
2.
3.1
2014-11-26
Winter CHEN
3.
4.
M35_User_Manual
Added information for SIM2 interface, DTR and
DCD pin.
Added information for Multi UART.
Modified module’s current consumption.
Modified module’s pin definition.
Modified DC characteristics of module pin.
Added information for PCM interface.
Updated Figure 5: Reference Circuit for Power
Supply.
Modified over-voltage or under-voltage
automatic shutdown in Section 3.4.2
Modified RTC backup in Section 3.6
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5.
6.
7.
M35_User_Manual
Modified UART application in Section 3.7.3
Modified SIM card interface in Section 3.10
Added antenna requirement in Section 4.5
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GSM/GPRS Module Series
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Contents
About the Document ................................................................................................................................... 2
Contents ....................................................................................................................................................... 4
Table Index ................................................................................................................................................... 7
Figure Index ................................................................................................................................................. 8
Introduction ........................................................................................................................................ 10
1.1.
Safety Information ................................................................................................................. 11
Product Concept ................................................................................................................................ 12
2.1.
General Description ............................................................................................................... 12
2.2.
Directives and Standards ...................................................................................................... 12
2.2.1. FCC Radiation Exposure Statement.............................................................................. 12
2.3.
Key Features ......................................................................................................................... 13
2.4.
Functional Diagram ............................................................................................................... 15
2.5.
Evaluation Board ................................................................................................................... 16
Application Interface ......................................................................................................................... 17
3.1.
Pin of Module......................................................................................................................... 18
3.1.1. Pin Assignment .............................................................................................................. 18
3.1.2. Pin Description ............................................................................................................... 19
3.2.
Operating Modes ................................................................................................................... 23
3.3.
Power Supply ........................................................................................................................ 25
3.3.1. Power Features of Module ............................................................................................. 25
3.3.2. Decrease Supply Voltage Drop ...................................................................................... 25
3.3.3. Reference Design for Power Supply .............................................................................. 26
3.3.4. Monitor Power Supply .................................................................................................... 27
3.4.
Power On and Down Scenarios ............................................................................................ 27
3.4.1. Power On ....................................................................................................................... 27
3.4.2. Power Down ................................................................................................................... 29
3.4.2.1.
Power Down Module Using the PWRKEY Pin .................................................. 29
3.4.2.2.
Power Down Module Using AT Command ........................................................ 30
3.4.2.3.
Over-voltage or Under-voltage Automatic Shutdown........................................ 30
3.4.2.4.
Emergency Shutdown Using EMERG_OFF Pin ............................................... 31
3.4.3. Restart ............................................................................................................................ 32
3.5.
Power Saving ........................................................................................................................ 33
3.5.1. Minimum Functionality Mode ......................................................................................... 33
3.5.2. SLEEP Mode .................................................................................................................. 34
3.5.3. Wake Up Module from SLEEP Mode............................................................................. 34
3.5.4. Summary of State Transition.......................................................................................... 35
3.6.
RTC Backup .......................................................................................................................... 35
3.7.
Serial Interfaces..................................................................................................................... 37
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3.7.1. UART Port ...................................................................................................................... 39
3.7.1.1.
The Features of UART Port ............................................................................... 39
3.7.1.2.
The Connection of UART .................................................................................. 40
3.7.1.3.
Firmware Upgrade ............................................................................................. 42
3.7.2. Debug Port ..................................................................................................................... 42
3.7.3. UART Application ........................................................................................................... 43
3.8.
Audio Interfaces..................................................................................................................... 44
3.8.1. Decrease TDD Noise and Other Noise .......................................................................... 46
3.8.2. Microphone Interfaces Design ....................................................................................... 46
3.8.3. Receiver Interface Design .............................................................................................. 47
3.8.4. Earphone Interface Design ............................................................................................ 47
3.8.5. Loud Speaker Interface Design ..................................................................................... 48
3.8.6. Audio Characteristics ..................................................................................................... 48
3.9.
PCM Interface........................................................................................................................ 49
3.9.1. Configuration .................................................................................................................. 50
3.9.2. Timing ............................................................................................................................. 50
3.9.3. Reference Design .......................................................................................................... 52
3.9.4. AT Command ................................................................................................................. 52
3.10.
SIM Card Interfaces .............................................................................................................. 53
3.10.1. SIM Card Application...................................................................................................... 53
3.11.
Behaviors of The RI ............................................................................................................... 57
3.12.
Network Status Indication...................................................................................................... 58
3.13.
Operating Status Indication ................................................................................................... 59
Antenna Interface ............................................................................................................................... 61
4.1.
RF Reference Design ............................................................................................................ 61
4.2.
RF Output Power ................................................................................................................... 62
4.3.
RF Receiving Sensitivity........................................................................................................ 62
4.4.
Operating Frequencies .......................................................................................................... 63
4.5.
Antenna Requirement ........................................................................................................... 63
4.6.
RF Cable Soldering ............................................................................................................... 64
Electrical, Reliability and Radio Characteristics ............................................................................ 65
5.1.
Absolute Maximum Ratings................................................................................................... 65
5.2.
Operating Temperature ......................................................................................................... 65
5.3.
Power Supply Ratings ........................................................................................................... 66
5.4.
Current Consumption ............................................................................................................ 67
5.5.
Electro-static Discharge ........................................................................................................ 68
Mechanical Dimensions .................................................................................................................... 70
6.1.
Mechanical Dimensions of Module ....................................................................................... 70
6.2.
Recommended Footprint ....................................................................................................... 72
6.3.
Top View of the Module ......................................................................................................... 73
6.4.
Bottom View of the Module ................................................................................................... 73
Storage and Manufacturing .............................................................................................................. 74
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7.1.
7.2.
7.3.
Storage .................................................................................................................................. 74
Soldering ............................................................................................................................... 74
Packaging .............................................................................................................................. 75
7.3.1. Tape and Reel Packaging .............................................................................................. 75
Appendix A Reference....................................................................................................................... 78
Appendix B GPRS Coding Scheme ................................................................................................. 83
10 Appendix C GPRS Multi-slot Class .................................................................................................. 85
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Table Index
TABLE 1: MODULE KEY FEATURES ............................................................................................................... 13
TABLE 2: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE ........................ 15
TABLE 3: PIN DESCRIPTION ........................................................................................................................... 19
TABLE 4: MULTIPLEXED FUNCTIONS ............................................................................................................ 23
TABLE 5: OVERVIEW OF OPERATING MODES ............................................................................................. 23
TABLE 6: SUMMARY OF STATE TRANSITION ............................................................................................... 35
TABLE 7: LOGIC LEVELS OF THE UART INTERFACES ................................................................................ 38
TABLE 8: PIN DEFINITION OF THE UART INTERFACES .............................................................................. 38
TABLE 9: PIN DEFINITION OF AUDIO INTERFACE ....................................................................................... 44
TABLE 10: AOUT2 OUTPUT CHARACTERISTICS .......................................................................................... 45
TABLE 11: TYPICAL ELECTRET MICROPHONE CHARACTERISTICS ......................................................... 48
TABLE 12: TYPICAL SPEAKER CHARACTERISTICS .................................................................................... 48
TABLE 13: PIN DEFINITION OF PCM INTERFACE ......................................................................................... 49
TABLE 14: CONFIGURATION........................................................................................................................... 50
TABLE 15: QPCMON COMMAND DESCRIPTION .......................................................................................... 53
TABLE 16: QPCMVOL COMMAND DESCRIPTION ......................................................................................... 53
TABLE 17: PIN DEFINITION OF THE SIM INTERFACES ................................................................................ 54
TABLE 18: BEHAVIORS OF THE RI ................................................................................................................. 57
TABLE 19: WORKING STATE OF THE NETLIGHT .......................................................................................... 58
TABLE 20: PIN DEFINITION OF THE STATUS ................................................................................................ 59
TABLE 21: PIN DEFINITION OF THE RF_ANT ................................................................................................ 61
TABLE 22: THE MODULE CONDUCTED RF OUTPUT POWER .................................................................... 62
TABLE 23: THE MODULE CONDUCTED RF RECEIVING SENSITIVITY ....................................................... 62
TABLE 24: THE MODULE OPERATING FREQUENCIES ................................................................................ 63
TABLE 25: ANTENNA CABLE REQUIREMENTS ............................................................................................. 63
TABLE 26: ANTENNA REQUIREMENTS.......................................................................................................... 63
TABLE 27: ABSOLUTE MAXIMUM RATINGS .................................................................................................. 65
TABLE 28: OPERATING TEMPERATURE........................................................................................................ 65
TABLE 29: THE MODULE POWER SUPPLY RATINGS .................................................................................. 66
TABLE 30: THE MODULE CURRENT CONSUMPTION .................................................................................. 67
TABLE 31: THE ESD ENDURANCE (TEMPERATURE: 25ºC, HUMIDITY: 45%) ............................................ 69
TABLE 32: REEL PACKING .............................................................................................................................. 77
TABLE 33: RELATED DOCUMENTS ................................................................................................................ 78
TABLE 34: TERMS AND ABBREVIATIONS ...................................................................................................... 79
TABLE 35: DESCRIPTION OF DIFFERENT CODING SCHEMES .................................................................. 83
TABLE 36: GPRS MULTI-SLOT CLASSES ...................................................................................................... 85
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Figure Index
FIGURE 1: MODULE FUNCTIONAL DIAGRAM ............................................................................................... 16
FIGURE 2: PIN ASSIGNMENT ......................................................................................................................... 18
FIGURE 3: VOLTAGE RIPPLE DURING TRANSMITTING .............................................................................. 25
FIGURE 4: REFERENCE CIRCUIT FOR THE VBAT INPUT ........................................................................... 26
FIGURE 5: REFERENCE CIRCUIT FOR POWER SUPPLY ............................................................................ 26
FIGURE 6: TURN ON THE MODULE WITH AN OPEN-COLLECTOR DRIVER .............................................. 27
FIGURE 7: TURN ON THE MODULE WITH A BUTTON .................................................................................. 28
FIGURE 8: TURN-ON TIMING .......................................................................................................................... 28
FIGURE 9: TURN-OFF TIMING ........................................................................................................................ 29
FIGURE 10: AN OPEN-COLLECTOR DRIVER FOR EMERG_OFF ................................................................ 31
FIGURE 11: REFERENCE CIRCUIT FOR EMERG_OFF BY USING BUTTON .............................................. 32
FIGURE 12: TIMING OF RESTARTING SYSTEM ............................................................................................ 32
FIGURE 13: TIMING OF RESTARTING SYSTEM AFTER EMERGENCY SHUTDOWN ................................ 33
FIGURE 14: VRTC IS SUPPLIED BY A NON-CHARGEABLE BATTERY ........................................................ 36
FIGURE 15: VRTC IS SUPPLIED BY A RECHARGEABLE BATTERY ............................................................ 36
FIGURE 16: VRTC IS SUPPLIED BY A CAPACITOR ...................................................................................... 36
FIGURE 17: REFERENCE DESIGN FOR FULL-FUNCTION UART ................................................................ 40
FIGURE 18: REFERENCE DESIGN FOR UART PORT ................................................................................... 41
FIGURE 19: REFERENCE DESIGN FOR UART PORT WITH HARDWARE FLOW CONTROL .................... 41
FIGURE 20: REFERENCE DESIGN FOR FIRMWARE UPGRADE ................................................................. 42
FIGURE 21: REFERENCE DESIGN FOR DEBUG PORT ............................................................................... 43
FIGURE 22: LEVEL MATCH DESIGN FOR 3.3V SYSTEM.............................................................................. 43
FIGURE 23: SKETCH MAP FOR RS-232 INTERFACE MATCH ...................................................................... 44
FIGURE 24: REFERENCE DESIGN FOR AIN1&AIN2 ..................................................................................... 46
FIGURE 25: REFERENCE INTERFACE DESIGN OF AOUT1 ......................................................................... 47
FIGURE 26: EARPHONE INTERFACE DESIGN .............................................................................................. 47
FIGURE 27: LOUD SPEAKER INTERFACE DESIGN ...................................................................................... 48
FIGURE 28: LONG SYNCHRONIZATION & SIGN EXTENSION DIAGRAM ................................................... 51
FIGURE 29: LONG SYNCHRONIZATION & ZERO PADDING DIAGRAM....................................................... 51
FIGURE 30: SHORT SYNCHRONIZATION & SIGN EXTENSION DIAGRAM ................................................. 51
FIGURE 31: SHORT SYNCHRONIZATION & ZERO PADDING DIAGRAM .................................................... 52
FIGURE 32: REFERENCE DESIGN FOR PCM ............................................................................................... 52
FIGURE 33: REFERENCE CIRCUIT FOR SIM1 INTERFACE WITH 8-PIN SIM CARD HOLDER ................. 55
FIGURE 34: REFERENCE CIRCUIT FOR SIM1 INTERFACE WITH THE 6-PIN SIM CARD HOLDER ......... 55
FIGURE 35: REFERENCE CIRCUIT FOR SIM2 INTERFACE WITH THE 6-PIN SIM CARD HOLDER ......... 56
FIGURE 36: RI BEHAVIOR OF VOICE CALLING AS A RECEIVER ................................................................ 57
FIGURE 37: RI BEHAVIOR AS A CALLER ....................................................................................................... 58
FIGURE 38: RI BEHAVIOR OF URC OR SMS RECEIVED ............................................................................. 58
FIGURE 39: REFERENCE DESIGN FOR NETLIGHT ..................................................................................... 59
FIGURE 40: REFERENCE DESIGN FOR STATUS.......................................................................................... 60
FIGURE 41: REFERENCE DESIGN FOR RF .................................................................................................. 61
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FIGURE 42: RF SOLDERING SAMPLE ........................................................................................................... 64
FIGURE 43: M35 MODULE TOP AND SIDE DIMENSIONS (UNIT: MM) ......................................................... 70
FIGURE 44: M35 MODULE BOTTOM DIMENSIONS (UNIT: MM) ................................................................... 71
FIGURE 45: RECOMMENDED FOOTPRINT (UNIT: MM) ................................................................................ 72
FIGURE 46: TOP VIEW OF THE MODULE ...................................................................................................... 73
FIGURE 47: BOTTOM VIEW OF THE MODULE .............................................................................................. 73
FIGURE 48: RAMP-SOAK-SPIKE REFLOW PROFILE.................................................................................... 75
FIGURE 49: TAPE AND REEL SPECIFICATION .............................................................................................. 76
FIGURE 50: DIMENSIONS OF REEL ............................................................................................................... 77
FIGURE 51: RADIO BLOCK STRUCTURE OF CS-1, CS-2 AND CS-3 ........................................................... 83
FIGURE 52: RADIO BLOCK STRUCTURE OF CS-4 ....................................................................................... 84
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Introduction
This document defines the M35 module and describes its hardware interface which are connected with
your application and the air interface.
This document can help you quickly understand module interface specifications, electrical and
mechanical details. Associated with application notes and user guide, you can use M35 module to design
and set up mobile applications easily.
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1.1. Safety Information
The following safety precautions must be observed during all phases of the operation, such as usage,
service or repair of any cellular terminal or mobile incorporating M35 module. Manufacturers of the
cellular terminal should send the following safety information to users and operating personnel and to
incorporate these guidelines into all manuals supplied with the product. If not so, Quectel does not take on
any liability for your failure to comply with these precautions.
Full attention must be given to driving at all times in order to reduce the risk of an
accident. Using a mobie while driving (even with a handsfree kit) cause distraction
and can lead to an accident. You must comply with laws and regulations restrcting
the use of wireless devices while driving.
Switch off the cellular terminal or mobile before boarding an aircraft. Make sure it
switched off. The operation of wireless appliances in an aircraft is forbidden to
prevent interference with communication systems. Consult the airline staff about
the use of wireless devices on boarding the aircraft. If your device offers a Flight
Mode which must be enabled prior to boarding an aircraft.
Switch off your wireless device when in hospitals or clinics or other health care
facilities. These requests are desinged to prevent possible interference with
sentitive medical equipment.
Cellular terminals or mobiles operate over radio frequency signal and cellular
network and cannot be guaranteed to connect in all conditions, for example no
mobile fee or an invalid SIM card. While you are in this condition and need
emergent help, please remember using emergency call. In order to make or
receive call, the cellular terminal or mobile must be switched on and in a service
area with adequate cellular signal strength.
Your cellular terminal or mobile contains a transmitter and receiver. When it is ON ,
it receives and transmits radio frequency energy. RF interference can occur if it is
used close to TV set, radio, computer or other electric equipment.
In locations with potencially explosive atmospheres, obey all posted signs to turn
off wireless devices such as your phone or other cellular terminals. Areas with
potencially exposive atmospheres including fuelling areas, below decks on boats,
fuel or chemical transfer or storage facilities, areas where the air contains
chemicals or particles such as grain, dust or metal powders.
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Product Concept
2.1. General Description
M35 is a Quad-band GSM/GPRS engine that works at frequencies of GSM850MHz, EGSM900,
DCS1800 and PCS1900MHz. The M35 features GPRS multi-slot class 12 and supports the GPRS coding
schemes CS-1, CS-2, CS-3 and CS-4. For more details about GPRS multi-slot classes and coding
schemes, please refer to the Appendix B & C.
With a tiny profile of 19.9mm × 23.6mm × 2.65mm, the module can meet almost all the requirements for
M2M applications, including Vehicles and Personal Tracking, Security System, Wireless POS, Industrial
PDA, Smart Metering, and Remote Maintenance & Control, etc.
M35 is an SMD type module with LCC package, which can be easily embedded into applications. It
provides abundant hardware interfaces like Audio and UART Interface.
Designed with power saving technique, the current consumption of M35 is as low as 1.3 mA in SLEEP
mode when DRX is 5.
M35 is integrated with Internet service protocols, such as TCP/UDP, FTP and PPP. Extended AT
commands have been developed for you to use these Internet service protocols easily.
The module fully complies with the RoHS directive of the European Union.
2.2. Directives and Standards
The M35 module is designed to comply with the FCC statements. FCC ID: XMR201512M35
The Host system using M35, should have label indicated FCC ID: XMR201512M35.
2.2.1. FCC Radiation Exposure Statement
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment.
This equipment should be installed and operated with minimum distance 20cm between the radiator and
your body as well as kept minimum 20cm from radio antenna depending on the Mobile status of this
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module usage. This module should NOT be installed and operating simultaneously with other radio.
The manual of the host system, which uses M35 must include RF exposure warning statement to advice
user should keep minimum 20cm from the radio antenna of M35 module depending on the Mobile status.
Note: If a portable device (such as PDA) uses M35 module, the device needs to do permissive change
and SAR testing.
The following list of antenna is indicating the maximum permissible antenna gain.
Part
Number
Frequency
Range (MHz)
Peak
Gain
(XZ-V)
Average Gain
(XZ-V)
VSWR
Impedance
3R007A
GSM850:
TX 824-849MHz
RX 869-894MHz
PCS1900：
TX 1850-1910MHz
RX 1930-1990MHz
1 dBi typ.
1 dBi typ.
3 max
50Ω
Antenna gain including cable loss must not exceed 4.95 dBi of GSM 850 and 2.5 dBi of PCS 1900 for th
e purpose of satisfying the requirements of 2.1043 and 2.1091. The antenna(s) used for this
transmitter must be installed to provide a separation distance of at least 20cm from all persons and
must not be co-located or operated in conjunction with any antenna or transmitter not described
under this FCC ID. The final product operating with this transmitter must include operating
instructions and antenna installation instructions, for end-users and installers to satisfy RF exposure
compliance requirements. Compliance of this device in all final product configurations is the
responsibility of the Grantee. Installation of this device into specific final products may require the
submission of a Class II permissive change application containing data pertinent to RF Exposure,
spurious emissions, ERP/EIRP, and host/module authentication, or new application if appropriate.
Installation of this device into specific final products may require the submission of a Class II
permissive change application containing data pertinent to RF Exposure, spurious emissions,
ERP/EIRP, and host/module authentication, or new application if appropriate.
2.3. Key Features
The following table describes the detailed features of M35 module.
Table 1: Module Key Features
Feature
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Power Supply
Single supply voltage: 3.3V ~ 4.6V
Typical supply voltage: 4V
Power Saving
Typical power consumption in SLEEP mode: 1.3 mA @DRX=5
1.2 mA @DRX=9
Frequency Bands




GSM Class
Small MS
Transmitting Power


Class 4 (2W) at GSM850 and EGSM900
Class 1 (1W) at DCS1800 and PCS1900
GPRS Connectivity



GPRS multi-slot class 10 (default)
GPRS multi-slot class 1~10 (configurable)
GPRS mobile station class B






GPRS data downlink transfer: max. 85.6kbps
GPRS data uplink transfer: max. 85.6kbps
Coding scheme: CS-1, CS-2, CS-3 and CS-4
Support the protocols PAP (Password Authentication Protocol)
usually used for PPP connections
Internet service protocols :
TCP/UDP/FTP/PPP/HTTP/NTP/MMS/SMTP/PING
Support Packet Broadcast Control Channel (PBCCH)
Support Unstructured Supplementary Service Data (USSD)
Temperature Range



Normal operation: -35°C ~ +80°C
Restricted operation: -40°C ~ -35°C and +80°C ~ +85°C 1)
Storage temperature: -45°C ~ +90°C
SMS


Text and PDU mode
SMS storage: SIM card
SIM Interfaces
Support SIM card: 1.8V, 3V
Audio Features
Speech codec modes:
 Half Rate (ETS 06.20)
 Full Rate (ETS 06.10)
 Enhanced Full Rate (ETS 06.50/06.60/06.80)
 Adaptive Multi-Rate (AMR)
 Echo Suppression
 Noise Reduction
 Embedded one amplifier of class AB with maximum driving power up
to 870mW
UART Interfaces
UART Port:
 Seven lines on UART port interface
 Used for AT command, GPRS data
 Multiplexing function
DATA GPRS

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Quad-band: GSM850, EGSM900, DCS1800, PCS1900
The module can search these frequency bands automatically
The frequency bands can be set by AT command
Compliant to GSM Phase 2/2+
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 Support autobauding from 4800bps to 115200bps
Debug Port:
 Two lines on debug port interface DBG_TXD and DBG_RXD
 Debug Port can used for firmware debugging
Phonebook Management
Support phonebook types: SM, ME, FD, ON, MT
SIM Application Toolkit
Support SAT class 3, GSM 11.14 Release 99
Real Time Clock
Supported
Physical Characteristics
Size: 19.9±0.15 × 23.6±0.15 × 2.65±0.2mm
Weight: Approx. 2.5g
Firmware Upgrade
Firmware upgrade via UART Port
Antenna Interface
Connected to antenna pad with 50 Ohm impedance control
NOTE
1)
When the module works within this temperature range, the deviations from the GSM specification may
occur. For example, the frequency error or the phase error will be increased.
Table 2: Coding Schemes and Maximum Net Data Rates over Air Interface
Coding Scheme
1 Timeslot
2 Timeslot
4 Timeslot
CS-1
9.05kbps
18.1kbps
36.2kbps
CS-2
13.4kbps
26.8kbps
53.6kbps
CS-3
15.6kbps
31.2kbps
62.4kbps
CS-4
21.4kbps
42.8kbps
85.6kbps
2.4. Functional Diagram
The following figure shows a block diagram of M35 and illustrates the major functional parts.



Radio frequency part
Power management
The Peripheral interface
—Power supply
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—Turn-on/off interface
—UART interfaces
—RTC interface
—Audio interfaces
—PCM interface
—SIM interfaces
—RF interface
RF_ANT
ESD
RF PAM
VBAT
PMU
PWRKEY
EMERG_OFF
VRTC
RF Transceiver
26MHz
Reset
RTC
Serial
Interface
UART
PCM
Interface
PCM
Audio
Audio
BB&RF
SIM
Interfaces
Status&
Netlight
SIM
Interface
GPIO&
PWM
MEMORY
Figure 1: Module Functional Diagram
2.5. Evaluation Board
In order to help you to develop applications with M35, Quectel supplies an evaluation board (EVB),
RS-232 to USB cable, power adapter, earphone, antenna and other peripherals to control or test the
module. For details, please refer to the document [4].
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Application Interface
The module adopts LCC package and has 42 pins. The following chapters provide detailed descriptions
about these pins below:










Power supply
Power on/down
RTC
Serial interfaces
Audio interfaces
PCM interface
SIM interfaces
RI
NETLIGHT
STATUS
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3.1. Pin of Module
GND
RF_ANT
GND
GND
GND
GND
VBAT
VBAT
VRTC
3.1.1. Pin Assignment
40
39
38
37
36
35
34
33
32
AGND 1
31 SIM_GND
MIC2P 2
30 SIM1_CLK
MIC2N 3
29 SIM1_DATA
MIC1P 4
28 SIM1_RST
MIC1N 5
27 SIM1_VDD
Top view
SPK1N 6
26 RI/PCM_CLK
SPK1P 7
25 DCD/SIM2_RST
LOUDSPKN 8
24 RTS
LOUDSPKP 9
23 CTS
PWRKEY 10
22 TXD
EMERG_OFF 11
21 RXD
17
18
19
20
SIM2_CLK
SIM2_VDD
VDD_EXT
DTR/SIM1_PRESENCE
Power
16
SIM2_DATA
GND
42
PCM_IN
SIM
41
PCM_OUT
VBAT
15
DBG_TXD
14
DBG_RXD
STATUS/ PCM_SYNC
13
NETLIGHT
12
RF
UART
PCM
Other
Audio
Figure 2: Pin Assignment
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3.1.2. Pin Description
Table 3: Pin Description
Power Supply
PIN NAME
VBAT
VRTC
PIN NO.
33, 34
32
VDD_
EXT
19
GND
35,36,3
7,38, 40
I/O
I/O
DC
CHARACTERISTICS
COMMENT
Main power supply of
module:
VBAT=3.3V~4.6V
Vmax=4.6V
Vmin=3.3V
Vnorm=4.0V
Make sure that
supply sufficient
current in a
transmitting burst
typically rises to
1.6A.
Power supply for RTC
when VBAT is not supplied
for the system.
Charging for backup
battery or golden capacitor
when the VBAT is applied.
VImax=3.3V
VImin=1.5V
VInorm=2.8V
VOmax=3V
VOmin=2V
VOnorm=2.8V
Iout(max)=2mA
Iin≈10uA
If unused, keep
this pin open.
Vmax=2.9V
Vmin=2.7V
Vnorm=2.8V
Imax=20mA
1. If unused, keep
this pin open.
2. Recommend to
add a 2.2~4.7uF
bypass capacitor,
when using this
pin for power
supply.
COMMENT
DESCRIPTION
Supply 2.8V voltage for
external circuit.
Ground
Turn on/off
PIN NAME
PWRKEY
PIN NO.
10
I/O
DESCRIPTION
DC
CHARACTERISTICS
Power
on/off
key.
PWRKEY should be pulled
down for a moment to turn
on or turn off the system.
VILmax=
0.1×VBAT
VIHmin=
0.6×VBAT
VImax=3.1V
Emergency Shutdown
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PIN NAME
EMERG_
OFF
PIN NO.
11
DC
CHARACTERISTICS
I/O
DESCRIPTION
COMMENT
Emergency off. Pulled
down for at least 40ms,
which will turn off the
module in case of
emergency. Use it only
when shutdown via
PWRKEY or AT command
cannot be achieved.
VILmax=0.45V
VIHmin=1.35V
Vopenmax=1.8V
I/O
DESCRIPTION
DC
CHARACTERISTICS
COMMENT
Indicate module’s
operating status. Output
high level when module
turns on, while output low
level when module turns
off.
VOHmin=
0.85×VDD_EXT
VOLmax=
0.15×VDD_EXT
If unused, keep
these pins open.
DC
CHARACTERISTICS
COMMENT
Open
drain/collector
driver required in
cellular device
application.
If unused, keep
this pin open.
Module Indicator
PIN NAME
STATUS
PIN NO.
12
Audio Interfaces
PIN NAME
PIN NO.
I/O
DESCRIPTION
MIC1P
MIC1N
4,5
Channel 1 positive and
negative voice input
MIC2P
MIC2N
2,3
Channel 2 positive and
negative voice input
SPK1P
SPK1N
7,6
AGND
LOUD
SPKN
LOUD
SPKP
8,9
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1. If unused, keep
these pins open.
2. Support both
voice and ringtone
output.
Channel 1 positive and
negative voice output
Analog ground. Separate
ground connection for
external audio circuits.
If unused, keep
these pins open.
Refer to Section 3.8
Channel 3 positive and
negative voice output
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If unused, keep
this pin open.
1. If unused, keep
these pins open.
2. Integrate a
Class- AB
amplifier internally.
3. Support both
voice and ringtone
output.
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Network Status Indicator
PIN NAME
PIN NO.
I/O
DESCRIPTION
DC
CHARACTERISTICS
COMMENT
If unused, keep
this pin open.
COMMENT
13
Network status
indication
VOHmin=
0.85×VDD_EXT
VOLmax=
0.15×VDD_EXT
PIN NAME
PIN NO.
I/O
DESCRIPTION
DC
CHARACTERISTICS
DTR
20
Data terminal ready
NETLIGHT
UART Port
RXD
21
Receive data
TXD
22
Transmit data
RTS
24
Request to send
CTS
23
Clear to send
RI
26
Ring indication
DCD
25
Data carrier detection
PIN NAME
PIN NO.
I/O
DESCRIPTION
DBG_
TXD
15
Transmit data
DBG_
RXD
14
VILmin=0V
VILmax=
0.25×VDD_EXT
VIHmin=
0.75×VDD_EXT
VIHmax=
VDD_EXT+0.2
VOHmin=
0.85×VDD_EXT
VOLmax=
0.15×VDD_EXT
If only use TXD,
RXD and GND to
communicate,
recommended
connecting RTS to
GND via 0R
resistor and
keeping other pins
open.
Debug Port
DC
CHARACTERISTICS
COMMENT
Same as above
If unused, keep
these pins open.
COMMENT
Receive data
I/O
DESCRIPTION
DC
CHARACTERISTICS
Power supply for SIM1
card
The voltage can be
selected by software
automatically. Either
1.8V or 3V.
SIM1 clock
VOLmax=
0.15×SIM1_VDD
VOHmin=
0.85×SIM1_VDD
SIM Interfaces
PIN NAME
SIM1_
VDD
SIM1_
CLK
PIN NO
27
30
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All signals of SIM
interfaces should
be protected
against ESD with
a TVS diode array.
Maximum trace
length is 200mm
from the module
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SIM1_
DATA
SIM1_
RST
29
28
I/O
SIM1 data
VOLmax=
0.15×SIM1_VDD
VOHmin=
0.85×SIM1_VDD
SIM1 reset
VOLmax=
0.15×SIM1_VDD
VOHmin=
0.85×SIM1_VDD
SIM1 card detection.
VILmin=0V
VILmax=
0.25×VDD_EXT
VIHmin=
0.75×VDD_EXT
VIHmax=
VDD_EXT+0.2
SIM1_
PRESENCE
20
SIM_
GND
31
SIM ground
18
Power supply for SIM2
card
The voltage can be
selected by software
automatically. Either
1.8V or 3V.
SIM2 clock
VOLmax=
0.15×SIM2_VDD
VOHmin=
0.85×SIM2_VDD
SIM2 data
VOLmax=
0.15×SIM2_VDD
VOHmin=
0.85×SIM2_VDD
SIM2_
VDD
SIM2_
CLK
SIM2_
DATA
17
16
I/O
25
SIM2 reset
VOLmax=
0.15×SIM2_VDD
VOHmin=
0.85×SIM2_VDD
PIN NAME
PIN NO.
I/O
DESCRIPTION
DC
CHARACTERISTICS
RF_ANT
39
I/O
RF antenna pad
Impedance of 50Ω
I/O
DESCRIPTION
DC
CHARACTERISTICS
SIM2_
RST
pad to SIM card
holder.
RF Interface
COMMENT
PCM Interface
PIN NAME
PIN NO.
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PCM_
SYNC
12
PCM sync signal
PCM_
CLK
26
PCM clock signal
PCM_
OUT
41
PCM serial data output
PCM_IN
42
PCM serial data input
VILmin=-0.3V
VILmax=
0.25×VDD_EXT
VIHmin=
0.75×VDD_EXT
VIHmax=
VDD_EXT+0.2
VOHmin=
0.85×VDD_EXT
VOLmax=
0.15×VDD_EXT
The default
function is
STATUS after
startup.
The default
function is RI after
startup.
If unused, keep
these pins open.
Table 4: Multiplexed Functions
PIN NAME
PIN NO.
Function After Reset
Alternate Function1)
STATUS/PCM_SYNC
12
STATUS
PCM_SYNC
DTR/SIM1_PRESENCE
20
DTR
SIM1_PRESENCE
DCD/SIM2_RST
25
DCD
SIM2_RST
RI/PCM_CLK
26
RI
PCM_CLK
NOTE
1)
The alternate function can be configured through AT command. For details, please refer to the section
3.9 and section 3.10.
3.2. Operating Modes
The table below briefly summarizes the various operating modes in the following chapters.
Table 5: Overview of Operating Modes
Mode
Normal Operation
M35_User_Manual
Function
GSM/GPRS
Sleep
After enabling sleep mode by ―AT+QSCLK=1‖, the module
will automatically go into Sleep Mode if DTR is set to high
level and there is no interrupt (such as GPIO interrupt or
data on UART port). In this case, the current consumption
of module will be reduced to the minimal level. During
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Sleep Mode, the module can still receive paging message
and SMS from the system normally.
GSM IDLE
Software is active. The module has registered to the GSM
network, and the module is ready to send and receive
GSM data.
GSM TALK
GSM connection is ongoing. In this mode, the power
consumption is decided by the configuration of Power
Control Level (PCL), dynamic DTX control and the working
RF band.
GPRS IDLE
The module is not registered to GPRS network. The
module is not reachable through GPRS channel.
GPRS
STANDBY
The module is registered to GPRS network, but no GPRS
PDP context is active. The SGSN knows the Routing Area
where the module is located at.
GPRS READY
The PDP context is active, but no data transfer is ongoing.
The module is ready to receive or send GPRS data. The
SGSN knows the cell where the module is located at.
GPRS DATA
There is GPRS data in transfer. In this mode, power
consumption is decided by the PCL, working RF band and
GPRS multi-slot configuration.
POWER DOWN
Normal shutdown by sending the ―AT+QPOWD=1‖ command, using the
PWRKEY or the EMERG_OFF1) pin. The power management ASIC
disconnects the power supply from the base band part of the module, and
only the power supply for the RTC is remained. Software is not active. The
UART interfaces are not accessible. Operating voltage (connected to VBAT)
remains applied.
Minimum Functionality
Mode (without
Removing Power
Supply)
―AT+CFUN‖ command can set the module to a minimum functionality mode
without removing the power supply. In this case, the RF part of the module
will not work or the SIM card will not be accessible, or both RF part and SIM
card will be disabled, but the UART port is still accessible. The power
consumption in this case is very low.
NOTE
1)
Use the EMERG_OFF pin only when failing to turn off the module by the command ―AT+QPOWD=1‖
and the PWRKEY pin. For more details, please refer to the Section 3.4.2.4.
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3.3. Power Supply
3.3.1. Power Features of Module
The power supply is one of the key issues in designing GSM terminals. Because of the 577us radio burst
in GSM every 4.615ms, power supply must be able to deliver high current peaks in a burst period. During
these peaks, drops on the supply voltage must not exceed minimum working voltage of module.
For M35 module, the max current consumption could reach to 1.6A during a transmit burst. It will cause a
large voltage drop on the VBAT. In order to ensure stable operation of the module, it is recommended that
the max voltage drop during the transmit burst does not exceed 400mV.
4.615ms
577us
Burst:1.6A
IBAT
VBAT
Vdrop
Figure 3: Voltage Ripple during Transmitting
3.3.2. Decrease Supply Voltage Drop
The power supply range of the module is 3.3V to 4.6V. Make sure that the input voltage will never drop
below 3.3V even in a transmitting burst. If the power voltage drops below 3.3V, the module could turn off
automatically. For better power performance, it is recommended to place a 100uF tantalum capacitor with
low ESR (ESR=0.7Ω) and ceramic capacitor 100nF, 33pF and 10pF near the VBAT pin. The reference
circuit is illustrated in Figure 4.
The VBAT route should be wide enough to ensure that there is not too much voltage drop during transmit
burst. The width of trace should be no less than 2mm and the principle of the VBAT route is the longer
route, the wider trace.
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VBAT
C1
100uF
C2
100nF
C3
C4
10pF
33pF
0603
0603
GND
Figure 4: Reference Circuit for the VBAT Input
3.3.3. Reference Design for Power Supply
The power design for the module is very important, since the performance of power supply for the module
largely depends on the power source. The power supply is capable of providing the sufficient current up to
2A at least. If the voltage drop between the input and output is not too high, it is suggested to use a LDO
as module’s power supply. If there is a big voltage difference between the input source and the desired
output (VBAT), a switcher power converter is recommended to be used as a power supply.
Figure 5 shows a reference design for +5V input power source. The designed output for the power supply
is 4.0V and the maximum load current is 3A. In addition, in order to get a stable output voltage, a zener
diode is placed close to the pins of VBAT. As to the zener diode, it is suggested to use a zener diode of
which reverse zener voltage is 5.1V and dissipation power is more than 1 Watt.
MIC29302WU
U1
DC_IN
VBAT
470uF
ADJ
R1
51K
GND
C1
C2
OUT 4
EN
2 IN
R2
124K
R4
R3
56K
100nF
470R
C3
470uF
C4
D1
100nF
5.1V
R5
4.7K
MCU_POWER_ON/OFF
R6
47K
Figure 5: Reference Circuit for Power Supply
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NOTE
It is suggested to control the module’s main power supply (VBAT) via LDO enable pin to restart the
module when the module has become abnormal. Power switch circuit like P-channel MOSFET switch
circuit can also be used to control VBAT.
3.3.4. Monitor Power Supply
The command ―AT+CBC‖ can be used to monitor the supply voltage of the module. The unit of the
displayed voltage is mV.
For details, please refer to the document [1].
3.4. Power On and Down Scenarios
3.4.1. Power On
The module can be turned on by driving the pin PWRKEY to a low level voltage. An open collector driver
circuit is suggested to control the PWRKEY. A simple reference circuit is illustrated as below.
PWRKEY
4.7K
Turn on pulse
47K
Figure 6: Turn On the Module with an Open-collector Driver
NOTE
1. M35 module is set to autobauding mode (AT+IPR=0) by default. In the autobauding mode, URC
―RDY‖ is not reported to the host controller after module is powered on. When the module is powered
on after a delay of 4 or 5 seconds, it can receive AT command. Host controller should first send an
―AT‖ or ―at‖ string in order that the module can detect baud rate of host controller, it should continue to
send the next ‖AT‖ string until receiving ―OK‖ string from the module. Then enter ―AT+IPR=x;&W‖ to
set a fixed baud rate for the module and save the configuration to flash memory of the module. After
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these configurations, the URC ―RDY‖ would be received from the UART Port of the module every time
when the module is powered on. For more details, refer to the section ―AT+IPR‖ in document [1].
2. AT command response indicates module is turned on successfully, or else the module fails to be
turned on.
The other way to control the PWRKEY is through a button directly. A TVS component is indispensable to
be placed nearby the button for ESD protection. For the best performance, the TVS component must be
placed nearby the button. When pressing the key, electrostatic strike may generate from finger. A
reference circuit is shown in the following figure.
S1
PWRKEY
TVS
Close to
S1
Figure 7: Turn On the Module with a Button
The turn-on timing is illustrated as the following figure.
T1
54ms
VBAT
EMERG_OFF
(INPUT)
>1s
VIH > 0.6*VBAT
PWRKEY
(INPUT)
VIL<0.1*VBAT
VDD_EXT
(OUTPUT)
800ms
STATUS
(OUTPUT)
MODULE
STATUS
OFF
BOOTING
RUNNING
Figure 8: Turn-on Timing
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NOTE
1. Make sure that VBAT is stable before pulling down PWRKEY pin. The time of T1 is recommended as
100ms.
2. EMERG_OFF should be floated when it is unused.
3. For more details about the application of STATUS pin, please refer to the Chapter 3.13.
3.4.2. Power Down
The following procedures can be used to turn off the module:




Normal power down procedure: Turn off module using the PWRKEY pin.
Normal power down procedure: Turn off module using command ―AT+QPOWD=1‖.
Over-voltage or under-voltage automatic shutdown: Take effect when over-voltage or under-voltage
is detected.
Emergent power down procedure: Turn off module using the EMERG_OFF pin.
3.4.2.1.
Power Down Module Using the PWRKEY Pin
It is a safe way to turn off the module by driving the PWRKEY to a low level voltage for a certain time. The
power down scenario is illustrated in Figure 9.
VBAT
0.7s4.6V or <3.3V, the module would
automatically shut down itself.
If the voltage is <3.3V, the following URC will be presented:
UNDER_VOLTAGE POWER DOWN
If the voltage is >4.6V, the following URC will be presented:
OVER_VOLTAGE POWER DOWN
After that moment, no further AT commands can be executed. The module logs off from network and
enters power down mode, and only RTC is still active.
NOTE
1. These result codes do not appear when autobauding is active and DTE and DCE are not correctly
synchronized after start-up. The module is recommended to set to a fixed baud rate.
2. Over-voltage warning and shutdown function is disabled by default.
3.4.2.4.
Emergency Shutdown Using EMERG_OFF Pin
The module can be shut down by driving the pin EMERG_OFF to a low level voltage over 40ms and then
releasing it. The EMERG_OFF line can be driven by an open-drain/collector driver or a button. The circuit
is illustrated as the following figures.
EMERG_OFF
4.7K
Emergency
shutdown pulse
47K
Figure 10: An Open-collector Driver for EMERG_OFF
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S2
EMERG_OFF
TVS2
Close to S2
Figure 11: Reference Circuit for EMERG_OFF by Using Button
Be cautious to use the pin EMERG_OFF. It should only be used under emergent situation. For instance, if
the module is unresponsive or abnormal, the pin EMERG_OFF could be used to shut down the system.
Although turning off the module by EMERG_OFF is fully tested and nothing wrong detected, this
operation is still a big risk as it could cause destroying of the code or data area of the flash memory in the
module. Therefore, it is recommended that PWRKEY or AT command should always be the preferential
way to turn off the system.
3.4.3. Restart
The module can be restarted by driving the PWRKEY to a low level voltage for a certain time, which is
similar to the way of turning on module. In order to make the internal LDOs discharge completely after
turning off the module, it is recommended to delay about 500ms before restarting the module. The restart
timing is illustrated as the following figure.
PWRKEY
(INPUT)
STATUS
(OUTPUT)
Turn off
Delay >500ms
Restart
Pull down the PWRKEY
to turn on the module
Figure 12: Timing of Restarting System
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The module can also be restarted by the PWRKEY after emergency shutdown.
EMERG_OFF
(INPUT)
Pulldown >40ms
Delay >500ms
STATUS
(OUTPUT)
PWRKEY
(INPUT)
Figure 13: Timing of Restarting System after Emergency Shutdown
NOTE
For more details about the application of STATUS pin, please refer to the Chapter 3.13.
3.5. Power Saving
Based on system requirements, there are several actions to drive the module to enter low current
consumption status. For example, ―AT+CFUN‖ can be used to set module into minimum functionality
mode and DTR hardware interface signal can be used to lead system to SLEEP mode.
3.5.1. Minimum Functionality Mode
Minimum functionality mode reduces the functionality of the module to a minimum level. The consumption
of the current can be minimized when the slow clocking mode is activated at the same time. The mode is
set with the ―AT+CFUN‖ command which provides the choice of the functionality levels =0, 1, 4.



0: minimum functionality.
1: full functionality (default).
4: disable both transmitting and receiving of RF part.
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If the module is set to minimum functionality by ―AT+CFUN=0‖, the RF function and SIM card function
would be disabled. In this case, the UART port is still accessible, but all AT commands related with RF
function or SIM card function will be not available.
If the module has been set by the command with ―AT+CFUN=4‖, the RF function will be disabled, but the
UART port is still active. In this case, all AT commands related with RF function will be not available.
After the module is set by ―AT+CFUN=0‖ or ―AT+CFUN=4‖, it can return to full functionality by
―AT+CFUN=1‖.
For detailed information about ―AT+CFUN‖, please refer to the document [1].
3.5.2. SLEEP Mode
The SLEEP mode is disabled by default. You can enable it by ―AT+QSCLK=1‖. On the other hand, the
default setting is ―AT+QSCLK=0‖ and in this mode, the module cannot enter SLEEP mode.
When the module is set by the command with ―AT+QSCLK=1‖, you can control the module to enter or exit
from the SLEEP mode through pin DTR. When DTR is set to high level, and there is no on-air or hardware
interrupt such as GPIO interrupt or data on UART port, the module will enter SLEEP mode automatically.
In this mode, the module can still receive voice, SMS or GPRS paging from network, but the UART port
does not work.
3.5.3. Wake Up Module from SLEEP Mode
When the module is in the SLEEP mode, the following methods can wake up the module.



If the DTR Pin is set low, it would wake up the module from the SLEEP mode. The UART port will be
active within 20ms after DTR is changed to low level.
Receiving a voice or data call from network will wake up the module.
Receiving an SMS from network will wake up the module.
NOTE
DTR pin should be held at low level during communication between the module and DTE.
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3.5.4. Summary of State Transition
Table 6: Summary of State Transition
Next Mode
Current Mode
Power Down
Normal Mode
Power Down
Sleep Mode
Use PWRKEY
Normal Mode
AT+QPOWD, use PWRKEY
pin, or use EMERG_OFF pin
SLEEP Mode
Use PWRKEY pin, or use
EMERG_OFF pin
Use AT command
―AT+QSCLK=1‖ and pull
DTR up
Pull DTR down or
incoming voice call or
SMS or data call
3.6. RTC Backup
The RTC (Real Time Clock) function is supported. The RTC is designed to work with an internal power
supply.
There are three kinds of designs for RTC backup power:

Use VBAT as the RTC power source.
When the module is turned off and the main power supply (VBAT) is remained, the real time clock is still
active as the RTC core is supplied by VBAT. In this case, the VRTC pin can be kept floating.

Use VRTC as the RTC power source.
If the main power supply (VBAT) is removed after the module is turned off, a backup supply such as a
coin-cell battery (rechargeable or non-chargeable) or a super-cap can be used to supply the VRTC pin to
keep the real time clock active.

Use VBAT and VRTC as the RTC power source.
As only powering the VRTC pin to keep the RTC will lead an error about 5 minutes a day, it is
recommended to power VBAT and VRTC pin at the same time when RTC function is needed. The
recommended supply for RTC core circuits are shown as below.
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Module
RTC
Core
Power Supply
LDO/DCDC
VBAT
LDO
1.5K
VRTC
Non-chargeable
Backup Battery
Figure 14: VRTC Is Supplied by a Non-chargeable Battery
Module
RTC
Core
Power Supply
LDO/DCDC
VBAT
LDO
VRTC
1.5K
Rechargeable
Backup Battery
Figure 15: VRTC Is Supplied by a Rechargeable Battery
Module
RTC
Core
Power Supply
LDO/DCDC
VBAT
VRTC
LDO
1.5K
Large Capacitance
Capacitor
Figure 16: VRTC Is Supplied by a Capacitor
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For the choice of a rechargeable or non-chargeable coin-cell battery, please visit http://www.sii.co.jp/en/.
NOTE
If the module is only powered by VRTC , the real time will have an error about 5 minutes a day. If you want
to keep an accurate real time, please use VBAT to supply the RTC core.
3.7. Serial Interfaces
The module provides two serial ports: UART Port and Debug Port. The module is designed as a DCE
(Data Communication Equipment), following the traditional DCE-DTE (Data Terminal Equipment)
connection. Autobauding function supports baud rate from 4800bps to 115200bps.
The UART Port:







TXD: Send data to RXD of DTE.
RXD: Receive data from TXD of DTE.
RTS: Request to send.
CTS: Clear to send.
DTR: DTE is ready and inform DCE (this pin can wake up the module).
RI: Ring indicator (when the call, SMS, data of the module are coming, the module will output signal
to inform DTE).
DCD: Data carrier detection (the validity of this pin demonstrates the communication link is set up).
NOTE
Hardware flow control is disabled by default. When hardware flow control is required, RTS and CTS
should be connected to the host. AT command ―AT+IFC=2,2‖ is used to enable hardware flow control. AT
command ―AT+IFC=0,0‖ is used to disable the hardware flow control. For more details, please refer to the
document [1].
The Debug Port:


DBG_TXD: Send data to the COM port of computer.
DBG_RXD: Receive data from the COM port of computer.
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The logic levels are described in the following table.
Table 7: Logic Levels of the UART Interfaces
Parameter
Min.
Max.
Unit
VIL
0.25×VDD_EXT
VIH
0.75×VDD_EXT
VDD_EXT +0.2
VOL
0.15×VDD_EXT
VOH
0.85×VDD_EXT
VDD_EXT
Table 8: Pin Definition of the UART Interfaces
Interfaces
Pin No.
Pin Name
Description
Alternate Function
14
DBG_RXD
Receive data
15
DBG_TXD
Transmit data
20
1)
Data terminal ready
21
RXD
Receive data
22
TXD
Transmit data
23
CTS
Clear to send
24
RTS
Request to send
25
2)
Data carrier detection
SIM2_RST
26
3)
Ring indication
PCM_CLK
Debug Port
UART Port
DTR
DCD
RI
SIM1_PRESENCE
NOTE
1.
2.
3.
1)
DTR pin can be used as SIM1_PRESENCE pin via ―AT+QSIMDET‖ command.
When using the SIM2 interface, DCD pin can be used as SIM2_RST pin. For more details, please
refer to the document [6].
3)
When using the PCM interface, RI pin can be used as PCM_CLK.
2)
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3.7.1. UART Port
3.7.1.1.






The Features of UART Port
Seven lines on UART interface.
Contain data lines TXD and RXD, hardware flow control lines RTS and CTS, other control lines DTR,
DCD and RI.
Used for AT command, GPRS data, etc. Multiplexing function is supported on the UART Port. So far
only the basic mode of multiplexing is available.
Support the communication baud rates as the following:
300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600 and 115200.
The default setting is autobauding mode. Support the following baud rates for Autobauding function:
4800, 9600, 19200, 38400, 57600 and 115200.
The module disables hardware flow control by default. AT command ―AT+IFC=2,2‖ is used to enable
hardware flow control.
After setting a fixed baud rate or autobauding, please send ―AT‖ string at that rate. The UART port is
ready when it responds ―OK‖.
Autobauding allows the module to detect the baud rate by receiving the string ―AT‖ or ―at‖ from the host or
PC automatically, which gives module flexibility without considering which baud rate is used by the host
controller. Autobauding is enabled by default. To take advantage of the autobauding mode, special
attention should be paid according to the following requirements:
1. Synchronization between DTE and DCE:
When DCE (the module) powers on with the autobauding enabled, it is recommended to wait 4 to 5
seconds before sending the first AT character. After receiving the ―OK‖ response, DTE and DCE are
correctly synchronized.
If the host controller needs URC in the mode of autobauding, it must be synchronized firstly. Otherwise
the URC will be discarded.
2. Restrictions on autobauding operation:





The UART port has to be operated at 8 data bits, no parity and 1 stop bit (factory setting).
Only the strings ―AT‖ or ―at‖ can be detected (neither ―At‖ nor ―aT‖).
The Unsolicited Result Codes like ―RDY‖, ―+CFUN: 1‖ and ―+CPIN: READY‖ will not be indicated
when the module is turned on with autobauding enabled and not be synchronized.
Any other Unsolicited Result Codes will be sent at the previous baud rate before the module detects
the new baud rate by receiving the first ―AT‖ or ―at‖ string. The DTE may receive unknown characters
after switching to new baud rate.
It is not recommended to switch to autobauding from a fixed baud rate.
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
If autobauding is active it is not recommended to switch to multiplex mode.
NOTE
To assure reliable communication and avoid any problems caused by undetermined baud rate between
DCE and DTE, it is strongly recommended to configure a fixed baud rate and save it instead of using
autobauding after start-up. For more details, please refer to the Section ―AT+IPR‖ in document [1].
3.7.1.2.
The Connection of UART
The connection between module and host using UART Port is very flexible. Three connection styles are
illustrated as below.
Reference design for Full-Function UART connection is shown as below when it is applied in
modulation-demodulation.
Module (DCE)
PC (DTE)
UART port
Serial port
TXD
RXD
RTS
CTS
DTR
DCD
TXD
RXD
RTS
CTS
DTR
DCD
RI
RING
GND
GND
Figure 17: Reference Design for Full-Function UART
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Three-line connection is shown as below.
Module (DCE)
UART port
Host (DTE)
Controller
TXD
TXD
RXD
RXD
GND
RTS
GND
0R
Figure 18: Reference Design for UART Port
UART Port with hardware flow control is shown as below. This connection will enhance the reliability of
the mass data communication.
Host (DTE)
Controller
Module (DCE)
TXD
TXD
RXD
RXD
RTS
RTS
CTS
CTS
GND
GND
Figure 19: Reference Design for UART Port with Hardware Flow Control
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3.7.1.3.
Firmware Upgrade
The TXD, RXD can be used to upgrade firmware. The PWRKEY pin must be pulled down before firmware
upgrade. The reference circuit is shown as below:
Module (DCE)
IO Connector
UART port
TXD
TXD
RXD
RXD
GND
PWRKEY
GND
PWRKEY
Figure 20: Reference Design for Firmware Upgrade
NOTE
The firmware of module might need to be upgraded due to certain reasons. It is recommended to reserve
these pins in the host board for firmware upgrade.
3.7.2. Debug Port
As to Debug Port, there are two working modes, Standard Mode and Advanced Mode, which can be
switched through using AT command‖ AT+QEAUART‖. For more details, please refer to the document
[7].
In Standard Mode, it can be used to execute software debug and it can also connect to a peripheral
device. Furthermore, its default baud rate is 115200bps.
In Advanced Mode, it can only be used to execute software debug, capture the system’s log with Cather
Log tool and output the log. In this mode, its baud rate is 460800bps.
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The reference design for Debug Port is shown as below.
Module
Peripheral
DBG_TXD
TXD
DBG_RXD
RXD
GND
GND
Figure 21: Reference Design for Debug Port
3.7.3. UART Application
The reference design of 3.3V level match is shown as below. If the host is a 3V system, please change
the 5.6K resistor to 10K.
Module
Peripheral
/TXD
/RXD
/RTS
/CTS
GPIO
EINT
GPIO
1K
RXD
1K
TXD
1K
RTS
1K
CTS
1K
DTR
1K
RI
1K
DCD
GND
GND
5.6K
5.6K
5.6K
Voltage level:3.3V
Figure 22: Level Match Design for 3.3V System
NOTE
It is highly recommended to add the resistor divider circuit on the UART signal lines when the host’s level
is 3V or 3.3V. For the higher voltage level system, a level shifter IC could be used between the host and
the module. For more details about UART circuit design, please refer to document [8].
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The following circuit shows a reference design for the communication between module and PC. Since the
electrical level of module is 2.8V, so a RS-232 level shifter must be used. Note that you should assure the
IO voltage of level shifter which connects to module is 2.8V.
C1+
Module
1K
DCD
1K
CTS
1K
RI
1K
1K
DTR
1K
RTS
C1-
GND
GND
C2+
VCC
C2-
V-
3.3V
GND
T2OUT
T2IN
T1OUT
T3IN
T5OUT
T4IN
T3OUT
T5IN
T4OUT
/R1OUT
5.6K
RXD
GND
T1IN
1K
TXD
V+
R1OUT
R1IN
R2OUT
R2IN
R3OUT
R3IN
GND
GND
5.6K
5.6K
RS-232 Level Shifter
To PC Serial Port
Figure 23: Sketch Map for RS-232 Interface Match
Please visit vendor web site to select the suitable RS-232 level shifter IC, such as: http://www.exar.com/
and http://www.maximintegrated.com.
3.8. Audio Interfaces
The module provides two analogy input channels and two analogy output channels.
Table 9: Pin Definition of Audio Interface
Interfaces
Name
Pin NO.
Description
MIC1P
Channel 1 Microphone positive input
MIC1N
Channel 1 Microphone negative input
SPK1P
Channel 1 Audio positive output
SPK1N
Channel 1 Audio negative output
AGND
Form a pseudo-differential pair with SPK2P
AIN1/AOUT1
AIN2/AOUT2
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MIC2P
Channel 2 Microphone positive input
MIC2N
Channel 2 Microphone negative input
LOUDSPKP
Channel 2 Audio positive output
LOUDSPKN
Channel 2 Audio negative output
AIN1 and AIN2 can be used for input of microphone and line. An electret microphone is usually used.
AIN1 and AIN2 are both differential input channels.
AOUT1 is used for output of the receiver. This channel is typically used for a receiver built into a handset.
AOUT1 channel is a differential channel. If it is used as a speaker, an amplifier should be employed.
AOUT2 is used for loudspeaker output as it embedded an amplifier of class AB whose maximum drive
power is 870mW. AOUT2 is a differential channel.
AOUT2 also can be used for output of earphone, which can be used as a single-ended channel.
LOUDSPKP and AGND can establish a pseudo differential mode.
All of these two audio channels support voice and ringtone output, and so on, and can be switched by
―AT+QAUDCH‖ command. For more details, please refer to the document [1].
Use AT command ―AT+QAUDCH‖ to select audio channel:



0--AIN1/AOUT1, the default value is 0.
1--AIN2/AOUT2, this channel is always used for earphone.
2--AIN2/AOUT2, this channel is always used for loudspeaker.
For each channel, you can use AT+QMIC to adjust the input gain level of microphone. You can also use
―AT+CLVL‖ to adjust the output gain level of receiver and speaker. ―AT+QSIDET‖ is used to set the
side-tone gain level. For more details, please refer to the document [1].
Table 10: AOUT2 Output Characteristics
Item
RMS Power
M35_User_Manual
Condition
Min.
Type
Max.
Unit
8ohm load
VBAT=4.2v
THD+N=1%
870
mW
8ohm load
VBAT=3.3v
THD+N=1%
530
mW
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3.8.1. Decrease TDD Noise and Other Noise
The 33pF capacitor is applied for filtering out 900MHz RF interference when the module is transmitting at
EGSM900MHz. Without placing this capacitor, TDD noise could be heard. Moreover, the 10pF capacitor
here is for filtering out 1800MHz RF interference. However, the resonant frequency point of a capacitor
largely depends on the material and production technique. Therefore, you would have to discuss with its
capacitor vendor to choose the most suitable capacitor for filtering out GSM850MHz, EGSM900MHz,
DCS1800MHz and PCS1900MHz separately.
The severity degree of the RF interference in the voice channel during GSM transmitting period largely
depends on the application design. In some cases, EGSM900 TDD noise is more severe; while in other
cases, DCS1800 TDD noise is more obvious. Therefore, you can have a choice based on test results.
Sometimes, even no RF filtering capacitor is required.
The capacitor which is used for filtering out RF noise should be close to audio interface. Audio alignment
should be as short as possible.
In order to decrease radio or other signal interference, the position of RF antenna should be kept away
from audio interface and audio alignment. Power alignment and audio alignment should not be parallel,
and power alignment should be far away from audio alignment.
The differential audio traces have to be placed according to the differential signal layout rule.
3.8.2. Microphone Interfaces Design
AIN1 and AIN2 channels come with internal bias supply for external electret microphone. A reference
circuit is shown in the following figure.
Close to
Microphone
Close to Module
GND
10pF
0603
33pF
0603
GND
Differential
layout
10pF
0603
33pF
0603
10pF
0603
33pF
0603
10pF
0603
33pF
0603
MICP
Module
10pF
0603
MICN
10pF
0603
33pF
0603
33pF
0603
GND
GND
GND
ESD
Electret
Microphone
GND
GND
ESD
GND
Figure 24: Reference Design for AIN1&AIN2
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3.8.3. Receiver Interface Design
Close to speaker
GND
Differential layout
10pF
0603
33pF
0603
10pF
0603
33pF
0603
10pF
0603
33pF
0603
ESD
Module
SPK1P
SPK1N
ESD
GND
Figure 25: Reference Interface Design of AOUT1
3.8.4. Earphone Interface Design
Close to Module
Close to Socket
GND
MIC2N
Module
MIC2P
10pF
0603
33pF
0603
10pF
0603
33pF
0603
10pF
0603
33pF
0603
GND
Differential
layout
GND
GND
4.7uF
10pF
0603
33pF
0603
ESD
68R
GND
LOUDSPKP
AGND
0R
22uF
33pF
0603
10pF
0603
ESD
Amphenol
9001-8905-050
AGND
AGND
GND
GND
GND
Figure 26: Earphone Interface Design
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3.8.5. Loud Speaker Interface Design
Close to Speaker
GND
Differential
layout
GND
GND
ESD
33pF
0603
10pF
0603
0R
LOUDSPKP
Module
10pF
0603
33pF
0603
0R
LOUDSPKN
8 ohm
33pF
0603
10pF
0603
ESD
GND
GND
GND
Figure 27: Loud Speaker Interface Design
3.8.6. Audio Characteristics
Table 11: Typical Electret Microphone Characteristics
Parameter
Min.
Typ.
Max.
Unit
Working Voltage
1.2
1.5
2.0
Working Current
200
500
uA
External Microphone Load Resistance
2.2
k Ohm
Table 12: Typical Speaker Characteristics
Parameter
Min.
Load resistance
AOUT1
Output
Typ.
Max.
32
Unit
Ohm
Single-ended
Ref level
Differential
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Ref level
Load resistance
4.8
Vpp
Load Resistance
Differential
Reference level
AOUT2
Output
Load resistance
2×VBAT
Vpp
Load Resistance
Single-ended
Reference level
VBAT
Vpp
3.9. PCM Interface
Pulse-code modulation (PCM) is a converter that changes the consecutive analog audio signal to discrete
digital signal. The whole procedure of Pulse-code modulation contains sampling, quantizing and
encoding.
M35 supports PCM interface. It is used for digital audio transmission between the module and the device.
This interface is composed of PCM_CLK, PCM_SYNC, PCM_IN and PCM_OUT signal lines.
The module disables PCM interface by default. AT command ―AT+QPCMON‖ is used to configure PCM
interface.
Table 13: Pin Definition of PCM Interface
Pin NO.
Pin Name
Description
1)
12
PCM_SYNC
PCM frame synchronization output
STATUS
26
PCM_CLK
PCM clock output
RI
41
PCM_OUT
PCM data output
42
PCM_IN
PCM data input
Alternate Function
NOTE
1)
When using the PCM interface, STATUS pin can be used as PCM_SYNC pin, RI pin can be used as
PCM_CLK pin.
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3.9.1. Configuration
M35 module supports 13-bit line code PCM format. The sample rate is 8 KHz, and the clock source is 256
KHz, and the module can only act as master mode. The PCM interface supports both long and short
synchronization simultaneously. Furthermore, it only supports MSB first. For detailed information, please
refer to the table below.
Table 14: Configuration
PCM
Line Interface Format
Linear
Data Length
Linear: 13 bits
Sample Rate
8KHz
PCM Clock/Synchronization Source
PCM master mode: clock and synchronization is
generated by module
PCM Synchronization Rate
8KHz
PCM Clock Rate
PCM master mode: 256 KHz (line)
PCM Synchronization Format
Long/short synchronization
PCM Data Ordering
MSB first
Zero Padding
Yes
Sign Extension
Yes
3.9.2. Timing
The sample rate of the PCM interface is 8 KHz and the clock source is 256 KHz, so every frame contains
32 bits data, since M35 supports 16 bits line code PCM format, the left 16 bits are invalid. The following
diagram shows the timing of different combinations. The synchronization length in long synchronization
format can be programmed by firmware from one bit to eight bits. In the Sign extension mode, the high
three bits of 16 bits are sign extension, and in the Zero padding mode, the low three bits of 16 bits are
zero padding.
Under zero padding mode, you can configure the PCM input and output volume by executing
―AT+QPCMVOL‖ command. For more details, please refer to Chapter 3.9.4.
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PCM_CLK
PCM_SYNC
MSB
PCM_OUT
Sign
extension
12 11 10
12 11 10 9
MSB
PCM_IN
Sign
extension
Figure 28: Long Synchronization & Sign Extension Diagram
PCM_CLK
PCM_SYNC
MSB
PCM_OUT
12 11 10 9
Zero padding
Zero padding
MSB
PCM_IN
12 11 10 9
Figure 29: Long Synchronization & Zero Padding Diagram
PCM_CLK
PCM_SYNC
MSB
PCM_OUT
Sign extension
12 11 10
12 11 10
MSB
PCM_IN
Sign extension
Figure 30: Short Synchronization & Sign Extension Diagram
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PCM_CLK
PCM_SYNC
MSB
PCM_OUT
12 11 10
0 Zero padding
0 Zero padding
MSB
PCM_IN
12 11 10
Figure 31: Short Synchronization & Zero Padding Diagram
3.9.3. Reference Design
M35 can only work as a master, providing synchronization and clock source. The reference design is
shown as below.
Peripheral
(Slave)
Module
(Master)
PCM_CLK
PCM_CLK
PCM_SYNC
PCM_SYNC
PCM_OUT
PCM_IN
PCM_OUT
PCM_IN
Figure 32: Reference Design for PCM
3.9.4. AT Command
There are two AT commands about the configuration of PCM, listed as below.
―AT+QPCMON‖ can configure operating mode of PCM.
AT+QPCMON=mode, Sync_Type, Sync_Length, SignExtension, MSBFirst.
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Table 15: QPCMON Command Description
Parameter
Scope
Description
Mode
0~2
0: Close PCM
1: Open PCM
2: Open PCM when audio talk is set up
Sync_Type
0~1
0: Short synchronization
1: Long synchronization
Sync_Length
1~8
Programmed from one bit to eight bit
SignExtension
0~1
0: Zero padding
1: Sign extension
MSBFirst
0~1
0: MSB first
1: Not support
―AT+QPCMVOL‖ can configure the volume of input and output.
AT+QPCMVOL=vol_pcm_in, vol_pcm_out
Table 16: QPCMVOL Command Description
Parameter
Scope
Description
vol_pcm_in
0~32767
Set the input volume
vol_pcm_out
0~32767
Set the output volume
The voice may be distorted when this value exceeds 16384.
3.10.
SIM Card Interfaces
The module contains two smart interfaces to allow module access to the two SIM cards. These two SIM
interfaces share the same ground and only SIM1 interface has card inserted detection. Only one SIM card
can work at a time. For more details, please refer to the document [6].
3.10.1. SIM Card Application
The SIM interfaces supports the functionality of the GSM Phase 1 specification and also supports the
functionality of the new GSM Phase 2+ specification for FAST 64 kbps SIM card, which is intended for
use with a SIM application Tool-kit.
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The SIM interfaces are powered by an internal regulator in the module. Both 1.8V and 3.0V SIM Cards
are supported.
Table 17: Pin Definition of the SIM Interfaces
1)
Pin NO.
Name
Description
27
SIM1_VDD
Supply power for SIM1 card. Automatic detection of
SIM1 card voltage. 3.0V±5% and 1.8V±5%.
Maximum supply current is around 10mA.
30
SIM1_CLK
SIM1 card clock.
29
SIM1_DATA
SIM1 card data I/O.
28
SIM1_RST
SIM1 card reset.
20
SIM1_PRESENCE
SIM1 card detection.
31
SIM_GND
SIM card ground.
18
SIM2_VDD
Supply power for SIM2 card. Automatic detection of
SIM2 card voltage. 3.0V±5% and 1.8V±5%.
Maximum supply current is around 10mA.
17
SIM2_CLK
SIM2 card clock.
16
SIM2_DATA
SIM2 card data I/O.
25
SIM2_RST
SIM2 card reset.
Alternate
Function
DTR
DCD
NOTE
1)
If several interfaces share the same I/O pin, to avoid conflict between these alternate functions, only one
peripheral should be enabled at a time.
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The following figure is the reference design for SIM1 interface.
VDD_EXT
10K
SIM_GND
Module
100nF
SIM1_VDD
SIM1_RST
SIM1_CLK
SIM1_PRESENCE
SIM1_DATA
SIM_Holder
VCC
RST
22R
22R
CLK
GND
VPP
IO
22R
GND
33pF 33pF33pF33pF
TVS
GND
GND
Figure 33: Reference Circuit for SIM1 Interface with 8-pin SIM Card Holder
If SIM1 card detection function is not used, keep SIM1_PRESENCE pin open. The reference circuit for a
6-pin SIM card socket is illustrated as the following figure.
SIM_GND
Module
100nF
SIM1_VDD
SIM1_RST
SIM1_CLK
SIM1_PRESENCE
SIM1_DATA
SIM_Holder
VCC
RST
CLK
22R
22R
GND
VPP
IO
22R
33pF33pF 33pF 33pF
TVS
GND
GND
Figure 34: Reference Circuit for SIM1 Interface with the 6-pin SIM Card Holder
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The following figure is the reference design for SIM2 interface with the 6-pin SIM card holder.
SIM_GND
Module
100nF
SIM2_VDD
SIM2_RST
SIM2_CLK
SIM2_DATA
SIM_Holder
VCC
RST
CLK
22R
22R
GND
VPP
IO
22R
33pF33pF 33pF 33pF
TVS
GND
GND
Figure 35: Reference Circuit for SIM2 Interface with the 6-pin SIM Card Holder
For more information
http://www.molex.com.
of
SIM
card
holder,
you
can
visit
http://www.amphenol.com
and
In order to enhance the reliability and availability of the SIM card in application. Please follow the below
criteria in the SIM circuit design.






Keep layout of SIM card as close as possible to the module. Assure the possibility of the length of the
trace is less than 200mm.
Keep SIM card signal away from RF and VBAT alignment.
Assure the ground between module and SIM cassette short and wide. Keep the width of ground no
less than 0.5mm to maintain the same electric potential. The decouple capacitor of SIM_VDD is less
than 1uF and must be near to SIM cassette.
To avoid cross talk between SIM_DATA and SIM_CLK. Keep them away with each other and shield
them with surrounded ground
In order to offer good ESD protection, it is recommended to add a TVS diode array. For more
information of TVS diode, you can visit http://www.onsemi.com/. The most important rule is to place
your ESD protection device close to the SIM card socket and make sure the net being protected will
go through the ESD device first and then lead to module. The 22Ω resistors should be connected in
series between the module and the SIM card so as to suppress the EMI spurious transmission and
enhance the ESD protection. Please to be noted that the SIM peripheral circuit should be close to the
SIM card socket.
Place the RF bypass capacitors (33pF) close to the SIM card on all signals line for improving EMI.
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3.11.
Behaviors of The RI
When using PCM interface, RI pin can be used as PCM_CLK.
Table 18: Behaviors of the RI
State
RI Response
Standby
HIGH
Voice Calling
Change to LOW, then:
1. Change to HIGH when call is established.
2. Use ATH to hang up the call, RI changes to HIGH.
3. Calling part hangs up, RI changes to HIGH first, and changes to LOW for
120ms indicating ―NO CARRIER‖ as an URC, then changes to HIGH again.
4. Change to HIGH when SMS is received.
SMS
When a new SMS comes, the RI changes to LOW and holds low level for about
120ms, then changes to HIGH.
URC
Certain URCs can trigger 120ms low level on RI. For more details, please refer to
the document [1].
NOTE
If URC of SMS is disabled, the RI will not change.
If the module is used as a caller, the RI would maintain high except the URC or SMS is received. On the
other hand, when it is used as a receiver, the timing of the RI is shown as below.
HIGH
RI
Off-hook by“ATA”
On-hook by “ATH”
LOW
Idle
Ring
Figure 36: RI Behavior of Voice Calling as a Receiver
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HIGH
RI
LOW
Idle
Calling
Talking
On-hook
Idle
Figure 37: RI Behavior as a Caller
HIGH
120ms
RI
LOW
Idle or
Talking
URC or
SMS received
Figure 38: RI Behavior of URC or SMS Received
3.12.
Network Status Indication
The NETLIGHT signal can be used to drive a network status indicator LED. The working state of this pin
is listed in the following table.
Table 19: Working State of the NETLIGHT
State
Module Function
Off
The module is not running.
64ms On/800ms Off
The module is not synchronized with network.
64ms On/2000ms Off
The module is synchronized with network.
64ms On/600ms Off
The GPRS data transmission after dialing the PPP connection.
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A reference circuit is shown as below.
VBAT
Module
300R
NETLIGHT
4.7K
47K
Figure 39: Reference Design for NETLIGHT
3.13.
Operating Status Indication
The STATUS pin will output a high level after the module being turned on. but it is not recommended
connecting this pin to a MCU’s GPIO to judge whether the module is turn-on or not. The following LED
indicator circuit for STATUS pin can be used to indicate the state after the module has been turned on.
Table 20: Pin Definition of the STATUS
Name
Pin
Description
1)
STATUS
12
Indicate module operating status
PCM_SYNC
Alternate Function
NOTE
1)
When using PCM interface, STATUS pin can be used as PCM_SYNC.
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VBAT
Module
300R
STATUS
4.7K
47K
Figure 40: Reference Design for STATUS
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Antenna Interface
The Pin 39 is the RF antenna pad. The RF interface has an impedance of 50Ω.
Table 21: Pin Definition of the RF_ANT
Name
Pin
Description
GND
37
Ground
GND
38
Ground
RF_ANT
39
RF antenna pad
GND
40
Ground
4.1. RF Reference Design
The reference design for RF is shown as below.
0R
RF_ANT
Module
NM
NM
Figure 41: Reference Design for RF
M35 provides an RF antenna pad for antenna connection. The RF trace in host PCB connected to the
module RF antenna pad should be coplanar waveguide line or microstrip line, whose characteristic
impedance should be close to 50Ω. M35 comes with grounding pads which are next to the antenna pad in
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order to give a better grounding. Besides, a π-type match circuit is suggested to be used to adjust the RF
performance.
4.2. RF Output Power
Table 22: The Module Conducted RF Output Power
Frequency
Max.
Min.
GSM850
33dBm±2dB
5dBm±5dB
EGSM900
33dBm±2dB
5dBm±5dB
DCS1800
30dBm±2dB
0dBm±5dB
PCS1900
30dBm±2dB
0dBm±5dB
NOTE
In GPRS 4 slots TX mode, the max output power is reduced by 2.5dB. This design conforms to the GSM
specification as described in section 13.16 of 3GPP TS 51.010-1.
4.3. RF Receiving Sensitivity
Table 23: The Module Conducted RF Receiving Sensitivity
Frequency
Receive Sensitivity
GSM850
< -109dBm
EGSM900
< -109dBm
DCS1800
< -109dBm
PCS1900
< -109dBm
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4.4. Operating Frequencies
Table 24: The Module Operating Frequencies
Frequency
Receive
Transmit
ARFCH
GSM850
869~894MHz
824~849MHz
128~251
EGSM900
925~960MHz
880~915MHz
0~124, 975~1023
DCS1800
1805~1880MHz
1710~1785MHz
512~885
PCS1900
1930~1990MHz
1850~1910MHz
512~810
4.5. Antenna Requirement
The following table shows the requirement on GSM antenna.
Table 25: Antenna Cable Requirements
Type
Requirements
GSM850/EGSM900
Cable insertion loss <1dB
DCS1800/PCS1900
Cable insertion loss <1.5dB
Table 26: Antenna Requirements
Type
Requirements
Frequency Range
GSM850/EGSM900/DCS1800/PCS1900MHz.
VSWR
≤2
Gain (dBi)
Max Input Power (W)
50
Input Impedance (Ω)
50
Polarization Type
Vertical
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4.6. RF Cable Soldering
Soldering the RF cable to RF pad of module correctly will reduce the loss on the path of RF, please refer
to the following example of RF soldering.
Figure 42: RF Soldering Sample
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Electrical,
Reliability
and
Radio
Characteristics
5.1. Absolute Maximum Ratings
Absolute maximum ratings for power supply and voltage on digital and analog pins of module are listed in
the following table:
Table 27: Absolute Maximum Ratings
Parameter
Min.
Max.
Unit
VBAT
-0.3
+4.73
Peak Current of Power Supply
RMS Current of Power Supply (during one TDMA- frame)
0.7
Voltage at Digital Pins
-0.3
3.08
Voltage at Analog Pins
-0.3
3.08
Voltage at Digital/analog Pins in Power Down Mode
-0.25
0.25
5.2. Operating Temperature
The operating temperature is listed in the following table:
Table 28: Operating Temperature
Parameter
Min.
Typ.
Max.
Unit
Normal Temperature
-35
+25
+80
℃
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Restricted Operation1)
-40 ~ -35
+80 ~ +85
℃
Storage Temperature
-45
+90
℃
NOTE
1)
When the module works within this temperature range, the deviation from the GSM specification may
occur. For example, the frequency error or the phase error will be increased.
5.3. Power Supply Ratings
Table 29: The Module Power Supply Ratings
Parameter
VBAT
Description
Conditions
Min.
Typ.
Max.
Unit
Supply voltage
Voltage must stay within the
min/max values, including
voltage drop, ripple, and
spikes.
3.3
4.0
4.6
Voltage drop
during
transmitting
burst
Maximum power control level
on GSM850 and EGSM900.
400
mV
Power down mode
SLEEP mode @DRX=5
IVBAT
Average supply
current
M35_User_Manual
150
1.3
uA
mA
13
0.98
mA
mA
13
1.0
mA
mA
TALK mode
GSM850/EGSM9001)
DCS1800/PCS19002)
223/219
153/151
mA
mA
DATA mode, GPRS (3Rx,2Tx)
GSM850/EGSM9001)
DCS1800/PCS19002)
363/393
268/257
mA
mA
DATA mode, GPRS(2 Rx,3Tx)
GSM850/EGSM9001)
DCS1800/PCS19002)
506/546
366/349
mA
mA
Minimum functionality mode
AT+CFUN=0
IDLE mode
SLEEP mode
AT+CFUN=4
IDLE mode
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Peak supply
current (during
transmission
slot)
DATA mode, GPRS (4Rx,1Tx)
GSM850/EGSM9001)
DCS1800/PCS19002)
217/234
172/170
mA
mA
DATA mode, GPRS (1Rx,4Tx)
GSM850/EGSM9001)
DCS1800/PCS19002)
458/485
462/439
mA
mA
Maximum power control level
on GSM850 and EGSM900.
1.6
NOTE
1.
2.
3.
1)
Power control level PCL 5.
Power control level PCL 0.
Under the EGSM900 spectrum，the power of 1Rx and 4Tx has been reduced.
2)
5.4. Current Consumption
The values of current consumption are shown as below.
Table 30: The Module Current Consumption
Condition
Current Consumption
Voice Call
GSM850
@power level #5 <300mA, Typical 223mA
@power level #12, Typical 83mA
@power level #19, Typical 62mA
EGSM900
@power level #5 <300mA, Typical 219mA
@power level #12, Typical 83mA
@power level #19, Typical 63mA
DCS1800
@power level #0 <250mA, Typical 153mA
@power level #7, Typical 73mA
@power level #15, Typical 60mA
PCS1900
@power level #0 <250mA, Typical 151mA
@power level #7, Typical 76mA
@power level #15, Typical 61mA
GPRS Data
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DATA Mode, GPRS ( 3 Rx, 2Tx ) CLASS 10
GSM850
@power level #5 <550mA, Typical 363mA
@power level #12, Typical 131mA
@power level #19, Typical 91mA
EGSM900
@power level #5 <550mA, Typical 393mA
@power level #12, Typical 132mA
@power level #19, Typical 92mA
DCS1800
@power level #0 <450mA, Typical 268mA
@power level #7, Typical 112mA
@power level #15, Typical 88mA
PCS1900
@power level #0 <450mA, Typical 257mA
@power level #7, Typical 119mA
@power level #15, Typical 89mA
DATA Mode, GPRS ( 4 Rx,1Tx ) CLASS 10
GSM850
@power level #5 <350mA, Typical 216mA
@power level #12, Typical 103mA
@power level #19, Typical 83mA
EGSM900
@power level #5 <350mA, Typical 233mA
@power level #12, Typical 104mA
@power level #19, Typical 84mA
DCS1800
@power level #0 <300mA, Typical 171mA
@power level #7, Typical 96mA
@power level #15, Typical 82mA
PCS1900
@power level #0 <300mA, Typical 169mA
@power level #7, Typical 98mA
@power level #15, Typical 83mA
NOTE
GPRS Class 10 is the default setting. The module can be configured from GPRS Class 1 to Class 10.
Setting to lower GPRS class would make it easier to design the power supply for the module.
5.5. Electro-static Discharge
Although the GSM engine is generally protected against Electro-static Discharge (ESD), ESD protection
precautions should still be emphasized. Proper ESD handling and packaging procedures must be applied
throughout the processing, handling and operation of any applications using the module.
The measured ESD values of module are shown as the following table:
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Table 31: The ESD Endurance (Temperature: 25ºC, Humidity: 45%)
Tested Point
Contact Discharge
Air Discharge
VBAT,GND
±5KV
±10KV
RF_ANT
±5KV
±10KV
TXD, RXD
±2KV
±4KV
Others
±0.5KV
±1KV
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Mechanical Dimensions
This chapter describes the mechanical dimensions of the module.
6.1. Mechanical Dimensions of Module
Figure 43: M35 Module Top and Side Dimensions (Unit: mm)
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Figure 44: M35 Module Bottom Dimensions (Unit: mm)
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6.2. Recommended Footprint
frame line
frame line
Silksreen
Silksreen
Figure 45: Recommended Footprint (Unit: mm)
NOTE
The module should keep about 3mm away from other components in the host PCB.
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6.3. Top View of the Module
Figure 46: Top View of the Module
6.4. Bottom View of the Module
Figure 47: Bottom View of the Module
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Storage and Manufacturing
7.1. Storage
M35 module is distributed in a vacuum-sealed bag. The restriction for storage is shown as below.
Shelf life in the vacuum-sealed bag: 12 months at environments of <40ºC temperature and <90%RH.
After the vacuum-sealed bag is opened, devices that need to be mounted directly must be:


Mounted within 72 hours at the factory environment of ≤30ºC temperature and <60% RH.
Stored at <10% RH.
Devices require baking before mounting, if any circumstance below occurs.



When the ambient temperature is 23ºC±5ºC, humidity indication card shows the humidity is >10%
before opening the vacuum-sealed bag.
If ambient temperature is <30ºC and the humidity is <60%, the devices have not been mounted
during 72hours.
Stored at >10% RH.
If baking is required, devices should be baked for 48 hours at 125ºC±5ºC.
NOTE
As plastic container cannot be subjected to high temperature, devices must be removed prior to high
temperature (125ºC) bake. If shorter bake times are desired, refer to the IPC/JEDECJ-STD-033 for bake
procedure.
7.2. Soldering
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The squeegee should push the paste on the surface of the stencil that makes the paste fill the stencil
openings and penetrate to the PCB. The force on the squeegee should be adjusted so as to produce a
clean stencil surface on a single pass. To ensure the module soldering quality, the thickness of stencil at
the hole of the module pads should be 0.2 mm for M35. For more details, please refer to document [5].
It is suggested that peak reflow temperature is from 235ºC to 245ºC (for SnAg3.0Cu0.5 alloy). Absolute
max reflow temperature is 260ºC. To avoid damage to the module when it was repeatedly heated, it is
suggested that the module should be mounted after the first panel has been reflowed. The following
picture is the actual diagram which we have operated.
℃
Preheat
Heating
Cooling
250
Liquids
Temperature
217
200℃
200
40s~60s
160℃
150
70s~120s
100
Between 1~3℃/S
50
50
100
150
200
250
300
Time(s)
Figure 48: Ramp-Soak-Spike Reflow Profile
7.3. Packaging
The modules are stored inside a vacuum-sealed bag which is ESD protected. It should not be opened
until the devices are ready to be soldered onto the application.
7.3.1. Tape and Reel Packaging
The reel is 330mm in diameter and each reel contains 250 modules.
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Figure 49: Tape and Reel Specification
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DETAIL:A
PS
DETAIL:A
Figure 50: Dimensions of Reel
Table 32: Reel Packing
Model Name
M35
MOQ for MP
Minimum Package: 250pcs
Minimum Package×4=1000pcs
250pcs
Size: 370 × 350 × 56mm3
N.W: 0.63kg
G.W: 1.47kg
Size: 380 × 250 × 365mm3
N.W: 2.5kg
G.W: 6.4kg
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Appendix A Reference
Table 33: Related Documents
SN
Document Name
Remark
[1]
Quectel_M35_AT_Commands_Manual
AT commands manual
[2]
ITU-T Draft new recommendation V.25ter
Serial asynchronous automatic dialing and
control
[3]
GSM_UART_Application_Note
UART port application note
[4]
GSM_EVB_User_Guide
GSM EVB user guide
[5]
Module_Secondary_SMT_User_Guide
Module secondary SMT user guide
[6]
M35_Dual_SIM_Application_Notes_V3.0
M35 Dual SIM Application Notes
[7]
GSM_Multi_UART_Application_Note
M35 Multi UART Application Notes
[8]
Quectel_GSM_Module_Digital_IO_Application_Note
GSM module digital IO application note
[9]
GSM 07.07
Digital cellular telecommunications (Phase
2+); AT command set for GSM Mobile
Equipment (ME)
[10]
GSM 07.10
Support GSM 07.10 multiplexing protocol
GSM 07.05
Digital cellular telecommunications (Phase
2+); Use of Data Terminal Equipment –
Data Circuit terminating Equipment (DTE –
DCE) interface for Short Message Service
(SMS) and Cell Broadcast Service (CBS)
GSM 11.14
Digital cellular telecommunications (Phase
2+); Specification of the SIM Application
Toolkit for the Subscriber Identity module –
Mobile Equipment (SIM – ME) interface
GSM 11.11
Digital cellular telecommunications (Phase
2+); Specification of the Subscriber Identity
module – Mobile Equipment (SIM – ME)
interface
[11]
[12]
[13]
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[14]
[15]
GSM 03.38
Digital cellular telecommunications (Phase
2+); Alphabets and language-specific
information
GSM 11.10
Digital cellular telecommunications (Phase
2); Mobile Station (MS) conformance
specification; Part 1: Conformance
specification
Table 34: Terms and Abbreviations
Abbreviation
Description
ADC
Analog-to-Digital Converter
AMR
Adaptive Multi-Rate
ARP
Antenna Reference Point
ASIC
Application Specific Integrated Circuit
BER
Bit Error Rate
BOM
Bill of Material
BTS
Base Transceiver Station
CHAP
Challenge Handshake Authentication Protocol
CS
Coding Scheme
CSD
Circuit Switched Data
CTS
Clear To Send
DAC
Digital-to-Analog Converter
DRX
Discontinuous Reception
DSP
Digital Signal Processor
DCE
Data Communications Equipment (typically module)
DTE
Data Terminal Equipment (typically computer, external controller)
DTR
Data Terminal Ready
DTX
Discontinuous Transmission
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EFR
Enhanced Full Rate
EGSM
Enhanced GSM
EMC
Electromagnetic Compatibility
ESD
Electrostatic Discharge
ETS
European Telecommunication Standard
FCC
Federal Communications Commission (U.S.)
FDMA
Frequency Division Multiple Access
FR
Full Rate
GMSK
Gaussian Minimum Shift Keying
GPRS
General Packet Radio Service
GSM
Global System for Mobile Communications
G.W
Gross Weight
HR
Half Rate
I/O
Input/Output
IC
Integrated Circuit
IMEI
International Mobile Equipment Identity
Imax
Maximum Load Current
Inorm
Normal Current
kbps
Kilo Bits Per Second
LED
Light Emitting Diode
Li-Ion
Lithium-Ion
MO
Mobile Originated
MOQ
Minimum Order Quantity
MP
Manufacture Product
MS
Mobile Station (GSM engine)
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MT
Mobile Terminated
N.W
Net Weight
PAP
Password Authentication Protocol
PBCCH
Packet Switched Broadcast Control Channel
PCB
Printed Circuit Board
PDU
Protocol Data Unit
PPP
Point-to-Point Protocol
RF
Radio Frequency
RMS
Root Mean Square (value)
RTC
Real Time Clock
RX
Receive Direction
SIM
Subscriber Identification Module
SMS
Short Message Service
TDMA
Time Division Multiple Access
TE
Terminal Equipment
TX
Transmitting Direction
UART
Universal Asynchronous Receiver & Transmitter
URC
Unsolicited Result Code
USSD
Unstructured Supplementary Service Data
VSWR
Voltage Standing Wave Ratio
Vmax
Maximum Voltage Value
Vnorm
Normal Voltage Value
Vmin
Minimum Voltage Value
VIHmax
Maximum Input High Level Voltage Value
VIHmin
Minimum Input High Level Voltage Value
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VILmax
Maximum Input Low Level Voltage Value
VILmin
Minimum Input Low Level Voltage Value
VImax
Absolute Maximum Input Voltage Value
VImin
Absolute Minimum Input Voltage Value
VOHmax
Maximum Output High Level Voltage Value
VOHmin
Minimum Output High Level Voltage Value
VOLmax
Maximum Output Low Level Voltage Value
VOLmin
Minimum Output Low Level Voltage Value
Phonebook Abbreviations
LD
SIM Last Dialing phonebook (list of numbers most recently dialed)
MC
Mobile Equipment list of unanswered MT Calls (missed calls)
ON
SIM (or ME) Own Numbers (MSISDNs) list
RC
Mobile Equipment list of Received Calls
SM
SIM phonebook
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Appendix B GPRS Coding Sche
me
Four coding schemes are used in GPRS protocol. The differences between them are shown in the
following table.
Table 35: Description of Different Coding Schemes
USF
Pre-coded
USF
Radio Block
excl.USF and
BCS
BCS
1/2
181
CS-2
2/3
CS-3
3/4
CS-4
Scheme
Code
Rate
CS-1
Tail
Coded
Bits
Punctured
Bits
Data
Rate
Kb/s
40
456
9.05
268
16
588
132
13.4
312
16
676
220
15.6
12
428
16
456
21.4
Radio block structure of CS-1, CS-2 and CS-3 is shown as the figure below.
Radio Block
BCS
USF
Rate 1/2 convolutional coding
Puncturing
456 bits
Figure 51: Radio Block Structure of CS-1, CS-2 and CS-3
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GSM/GPRS Module Series
M35 User Manual
Radio block structure of CS-4 is shown as the following figure.
Radio Block
BCS
USF
Block
Code
No coding
456 bits
Figure 52: Radio Block Structure of CS-4
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GSM/GPRS Module Series
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10
Appendix C GPRS Multi-slot Class
Twenty-nine classes of GPRS multi-slot modes are defined for MS in GPRS specification. Multi-slot
classes are product dependant, and determine the maximum achievable data rates in both the uplink and
downlink directions. Written as 3+1 or 2+2, the first number indicates the amount of downlink timeslots,
while the second number indicates the amount of uplink timeslots. The active slots determine the total
number of slots the GPRS device can use simultaneously for both uplink and downlink communications.
The description of different multi-slot classes is shown in the following table.
Table 36: GPRS Multi-slot Classes
Multislot Class
Downlink Slots
Uplink Slots
Active Slots
10
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