Comba Telecom Network Systems RX4122-A UHF Public Safety Bi-directional Amplifier User Manual
Comba Telecom Ltd. UHF Public Safety Bi-directional Amplifier
User manual

UHF PUBLIC SAFETY 
BI-DIRECTIONAL 
AMPLIFIER 
USER MANUAL 
Public Safety BDA RX-4122 Class A QE: 1-0-0 
Comba Telecom Ltd. 
CriticalPoint Public Safety BDA 

INSTALLATION GUIDE FOR RX-4122 
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The  information  contained  herein  is  the  responsibility  of  and  is  approved  by  the 
following, to whom all enquiries should be directed: 
This  is an  unpublished  work the  copyright  in  which vests  in  Comba  International 
("Comba"). All rights reserved. 
The information contained herein is confidential and the property of Comba and is 
supplied  without  liability  for  errors  or  omissions.  No  part  may  be  reproduced, 
disclosed or used except as authorized by contract or other written permission. The 
copyright and the foregoing restriction on reproduction and use extend to all media 
in which the information may be embodied. 

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0.1  CONTENTS 
Section 
Page 
0.1 CONTENTS ....................................................................................................................................... 4 
0.2 INDEX TO FIGURES AND TABLES ............................................................................................. 6 
0.3 HISTORY ........................................................................................................................................... 7 
0.4 GLOSSARY OF TERMS ................................................................................................................. 8 
0.5 SAFETY NOTICES AND ADMONISHMENTS ............................................................................ 9 
1 GENERAL INFORMATION ........................................................................................................... 10 
2 EQUIPMENT DESCRIPTION ....................................................................................................... 11 
2.1 FUNCTIONAL BLOCK DIAGRAM ............................................................................................... 11 
2.2 EQUIPMENT LAYOUT .................................................................................................................. 12 
2.3 EQUIPMENT CONSTITUTION .................................................................................................... 13 
3 INSTALLATION .............................................................................................................................. 14 
3.1 WARNINGS AND ALERTS ........................................................................................................... 14 
3.2 SITE PLANNING CONSIDERATIONS ....................................................................................... 15 
3.2.1 SITE PLANNING ............................................................................................................................ 15 
3.2.2 INSTALLATION CHECKLIST ....................................................................................................... 16 
3.3 INSTALLATION PROCEDURES ................................................................................................. 17 
3.3.1 GOODS INWARDS INSPECTION............................................................................................... 17 
3.3.2 TOOLS ............................................................................................................................................. 17 
3.3.3 PREPARATION .............................................................................................................................. 17 
3.3.4 WALL MOUNTING ......................................................................................................................... 18 
3.3.5 DRIP-LOOP ..................................................................................................................................... 18 
3.4 EQUIPMENT CONNECTORS ...................................................................................................... 19 
3.4.1 PS BDA CONNECTORS ............................................................................................................... 19 
3.4.2 PS BDA LED Indicators ................................................................................................................. 21 
3.4.3 GROUNDING CONNECTION ...................................................................................................... 21 
3.4.4 RF CABLE CONNECTION ........................................................................................................... 21 
3.4.5 ETHERNET CONNECTION ......................................................................................................... 21 
3.4.6 DRY CONTACT CABLE CONNECTION .................................................................................... 22 
4 COMMISSIONING ......................................................................................................................... 24 
4.1 PRE-COMMISSIONING TASKS .................................................................................................. 24 
4.2 COMMISSIONING PROCEDURE ............................................................................................... 25 
5 WEB GUI ......................................................................................................................................... 27 
5.1 WEB GUI CONNECTION ............................................................................................................. 27 
5.2 WEB GUI INTRODUCTION .......................................................................................................... 28 
5.2.1 [DEVICES] ....................................................................................................................................... 28 
5.2.2 [COMMISSIONING] ....................................................................................................................... 29 
5.2.3 [FIRMWARE] ................................................................................................................................... 30 
5.2.4 [MANAGEMENT] ............................................................................................................................ 31 
5.3 COMMISSIONING PROCEDURE ............................................................................................... 42 
6 MAINTENANCE .............................................................................................................................. 47 
7 APPENDICES ................................................................................................................................. 48 
7.1 APPENDIX A: TOOLS ................................................................................................................... 48 
7.2 APPENDIX B: DECLARATION OF HARMFUL SUBSTANCES AND CONTENT ................ 49 

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0.2  INDEX TO FIGURES AND TABLES 
Figure 1: Front, Side and Bottom Views of the PS BDA Enclosure ................................................................. 10 
Figure 2: PS BDA Functional Block Diagram................................................................................................... 11 
Figure 3: Layout of the PS BDA ....................................................................................................................... 12 
Figure 4: Mounting Rack Overview .................................................................................................................. 17 
Figure 5: PS BDA Wall Mounting ..................................................................................................................... 18 
Figure 6: Equipment Connectors ..................................................................................................................... 19 
Figure 7: Commissioning Procedure ................................................................................................................ 25 
Figure 8: Input IP Address ............................................................................................................................... 27 
Figure 9: Input Domain Name .......................................................................................................................... 27 
Figure 10: Input User Name and Password ..................................................................................................... 27 
Figure 11: Web GUI Main Screen .................................................................................................................... 28 
Figure 12: Overview Screen............................................................................................................................. 28 
Figure 13: 400MHz Screen 1 ........................................................................................................................... 29 
Figure 14: 400MHz Screen 2 ........................................................................................................................... 29 
Figure 15: [Commissioning] Screen ................................................................................................................. 30 
Figure 16: [Firmware] Screen – MCU Firmware Upgrade ............................................................................... 30 
Figure 17: [Firmware] Screen – Firmware Swap ............................................................................................. 31 
Figure 18: [Firmware] Screen – Module Update .............................................................................................. 31 
Figure 19: [Management] Screen .................................................................................................................... 32 
Figure 20: Management – Import & Export ...................................................................................................... 33 
Figure 21: Management – IP Setting ............................................................................................................... 34 
Figure 22: Management – Comm. Setting ....................................................................................................... 35 
Figure 23: Management – Security .................................................................................................................. 36 
Figure 24: Modify Password............................................................................................................................. 37 
Figure 25: Management – Device Reset ......................................................................................................... 37 
Figure 26: Management – Device Info ............................................................................................................. 38 
Figure 27: Management – Isolation ................................................................................................................. 38 
Figure 28: Management – RF Setting .............................................................................................................. 39 
Figure 29: Management – Alarm Setting ......................................................................................................... 39 
Figure 30: Management – Report .................................................................................................................... 40 
Figure 31: Management – Alarm Log .............................................................................................................. 40 
Figure 32: Management – Clear History Alarm ................................................................................................ 41 
Figure 33: Commissioning Procedure – Start .................................................................................................. 42 
Figure 34: Commissioning Procedure – Site Info. Setting ............................................................................... 42 
Figure 35: Device Information Setting .............................................................................................................. 43 
Figure 37: Commissioning Procedure – Isolation Detection ............................................................................ 44 
Figure 38: Commissioning Procedure – Isolation Detection Confirm .............................................................. 44 
Figure 39: Commissioning Procedure – Isolation Detection Failed ................................................................. 44 
Figure 40: Commissioning Procedure – Isolation Detection Finish ................................................................. 45 
Figure 41: Commissioning Procedure – Center Frequency Setting ................................................................ 45 
Figure 42: Commissioning Procedure – Channel Number Setting .................................................................. 45 
Figure 43: Commissioning Procedure – Finish ................................................................................................ 46 
Table 1: Equipment Connectors ...................................................................................................................... 19 
Table 2: LED Indicators .................................................................................................................................... 21 
Table 3: Pin Definition of Dry Contact Cable ................................................................................................... 22 
Table 4: Commissioning Task Explanation ...................................................................................................... 26 

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0.3  HISTORY 
Change No. 
ENU 
Details Of Change 
1 
1-0-0 
This manual first created and issued in Jan. 2018. 
. 

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0.4  GLOSSARY OF TERMS 
Abbreviation  
Definition  
ALC  
Automatic Level Control  
ATT  
Attenuator 
BTS 
Base Transceiver Station 
CH 
Channel  
CSA 
Cross Sectional Area 
dB  
Decibel  
dBm  
Decibels relative to 1 milliwatt 
DL  
Downlink 
DT  
Donor Terminal  
DPX 
Duplexer 
FS 
Frequency Selection 
Hz  
Hertz  
ID 
Identification  
IF 
Intermediate Frequency 
LNA  
Low Noise Amplifier 
LOS 
Line-of-Sight 
MCU  
Main Control Unit  
MHz  
Megahertz  
MT  
Mobile Terminal  
MTBF  
Mean Time Between Failures  
NF  
Noise Figure  
OMC  
Operation & Maintenance Center  
OMT  
Operation & Maintenance Terminal 
PA 
Power Amplifier 
PLL  
Phase Locked Loop  
PSU  
Power Supply Unit  
RF  
Radio Frequency  
SMA  
Sub-Miniature A Connector  
UL  
Uplink  
VAC 
Volts Alternating Current 
VDC 
Volts Direct Current 
VSWR  
Voltage Standing Wave Ratio  

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0.5  SAFETY NOTICES AND ADMONISHMENTS 
This document contains safety notices in accordance with appropriate standards. In the interests of conformity 
with the territory standards for the country concerned, the equivalent territorial admonishments are also shown. 
Any installation, adjustment, maintenance and repair of the equipment must only be carried out by trained, 
authorized personnel. At all times, personnel must comply with any safety notices and instructions. 
Specific hazards are indicated by symbol labels on or near the affected parts of the equipment. The labels 
conform to international standards, are triangular in shape, and are colored black on a yellow background. An 
informative text label may accompany the symbol label. 
Hazard labeling is supplemented by safety notices in the appropriate equipment manual. These notices contain 
additional information on the nature of the hazard and may also specify precautions.  
Note: The grantee is not responsible for any changes or modifications not expressly approved by the party 
responsible for compliance. Such modifications could void the user’s authority to operate the equipment.  
For  compliance  with  the  general  population  RF  exposure  limits,  each  individual  antenna  used  for  this 
transmitter must be installed to provide a separation distance greater than 67.2cm or more from all persons 
during  normal  operation  and  must  not  be  co-located  with  any  other  antenna  for  meeting  RF  exposure 
requirements. 
Warning Notices: 
These draw the attention of personnel to hazards that may cause death or injury to the operator or others. 
Examples of use are cases of high voltage, laser emission, toxic substances, point of high temperature, etc. 
WARNING. This is NOT a CONSUMER device. It is designed for installation by FCC LICENSEES and 
QUALIFIED INSTALLERS. You MUST have an FCC LICENSE or express consent of an FCC Licensee to 
operate this device. The PS BDA can be configured as Class A Signal Booster. You MUST register 
Class  B  signal  boosters  (as  defined  in  47  CFR  90.219)  online  at 
www.fcc.gov/signal-boosters/registration.  Unauthorized  use  may  result  in  significant  forfeiture 
penalties, including penalties in excess of $100,000 for each continuing violation. 
Alert:  
These draw the attention of personnel to hazards that may cause damage to the equipment. An example of use 
is the case of static electricity hazard.  
Caution notices may also be used in the handbook to draw attention to matters that do not constitute a risk of 
causing damage to the equipment but where there is a possibility of seriously impairing its performance, e.g. by 
mishandling or gross maladjustment. Warnings and Cautions within the main text do not incorporate labels and 
may be in shortened form.  
Disconnection of the 2 RF connectors may cause damage to the equipment when power is on.  
The application antenna and RF cable are not provided. The antenna gain should not exceed 10 dBi.   
 End of Section 

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1  GENERAL INFORMATION 
The RX-4122 is a new digital public safety Bi-Directional repeater (hereafter referred to as PS BDA) designed 
to protect the lives of first responders and building occupants. Through the use of digital filtering technology, 
the  RX-4122  helps eliminate  adjacent  channel interference  to  allow  band selectivity and  support  400MHz 
rebanding.  
Main Features 
 PS UHF 400MHz. 
 Class A BDA, support 32 channels total. 
 Channel selective, software programmable. 
 Auto diagnostic. 
 Uplink squelch, per channel. 
 User adjustable gain control (AGC), UL and DL independent per channel. 
 Built in isolation testing (mandatory prior to commissioning the PS BDA). 
 Easy commission and setup via Web-based GUI. 
 Weatherproof enclosure, IP65/NEMA4X. 
 Fully compliant with the 2016 NFPA 1221 Code, FCC and UL standard. 
 Low AC power consumption: less than 85W 
 Weight: 77 lbs (not including mounting bracket and duplexers)  
 Alarming output to supervised circuits for: antenna failure, signal booster failure, and etc. 
The following figure shows the enclosure of the PS BDA. 
Figure 1: Front, Side and Bottom Views of the PS BDA Enclosure   

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2  EQUIPMENT DESCRIPTION 
2.1  FUNCTIONAL BLOCK DIAGRAM 
Mobile
Ant
Donor
Ant
Mobile
Power
Supply
Alarm
Indicator Main Control Unit
OMT
LAN
DT MT
BTS
DL Subband 01
BIAS 
Tee
DL Subband 02 PA
PA
DL_01
DL_02
UL_01
UL_02
DL_01
DL_02
UL Subband 01
UL Subband 02
UL_01
UL_02
Digital 
Integrated 
module
LNA
DL_01
DL_02
LNA
UL_01
UL_02
Figure 2: PS BDA Functional Block Diagram 
In the downlink path, the BTS signals are received by the donor antenna of the repeater. After the circulator, the 
signals are sent to downlink filter and then the LNA module for pre-amplification and to the digital RF integrated 
module for digital filtering and frequency conversion. Then the DL signals will be sent to the downlink PA to 
amplify power, and filter via downlink filter, the circulator, and last, the signals are transmitted at the MT port to 
the service antenna.  
In the uplink path, the mobile signals are received by the service antenna. After the circulator, the signals are 
sent to uplink filter, and then to LNA, digital integrated module for digital filtering, then to the PA for power 
amplification and to the uplink filter, the circulator, after that, the uplink signals are sent to the donor antenna for 
transmission back to the BTS. 

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2.2  EQUIPMENT LAYOUT 
Shown below is the internal layout of the PS BDA. 
黑色开关
MT
DT
避雷器
DL FilterUL Filter
DL FilterUL Filter
DT
/DL IN MT
/DL OUT UL IN UL OUT
Front Side of 3rd Layer 
(Passive Unit)
Back Side of 2nd 
Layer 
Front Side of 2nd Layer 
(Passive Unit)
Loop
Circulator
Circulator
UL Filter DL Filter
DL FilterUL Filter
PSU
Distribution 
Board MCU
+28V
+28V
GND
RF OUT
RF IN
+28V
GND
RF OUT
RF IN
DL PA
Digital Integrated 
Module
+28V
Ref IN
LNA1 OUT
LNA1 IN
LNA2 IN
LNA2 OUT
UL IN
UL OUT
DL OUT
DL IN
UL PA
OUT4
IN4
OUT3IN3OUT2
IN2
OUT1
IN1
LAN
RUN
ALM
PWR
OMT
Figure 3: Layout of the PS BDA  

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2.3  EQUIPMENT CONSTITUTION 
The typical PS BDA unit consists of the following components:  
Downlink Power Amplifier (DPA): It provides power amplification for DL branches.  
Uplink Power Amplifier (UPA): It provides power amplification for UL branches. 
Main  Control Unit  (MCU):  The MCU is used to monitor and control the operation of the repeater. It also 
provides  the communication interface  for  remote control  and  status indication. LED indicators provide the 
operation status of the MCU. 
Downlink Filter: The filter is used to restrain the uplink signals to achieve a better isolation between downlink 
path and uplink path, to make sure the device can work in a normal duplex mode. 
Uplink Filter: The filter is used to restrain the downlink signals to achieve a better isolation between downlink 
path and uplink path, to make sure the device can work in a normal duplex mode. 
Digital Integrated Module: Consists of RF module, digital process module and monitoring modules. The RF 
module amplifies and converts the RF signal to IF signal. The Digital process module converts the IF signal into 
baseband signal via AD conversion and extraction, and filtering. After that, the IF signal will be amplified and 
converted to an RF signal by the RF module for RF filtering and amplification. The Monitoring module monitors 
and controls the system parameters and it is the interface for both remote monitoring and local commissioning, 
and at the same time control the charge and discharge of the backup battery. 
Power Supply Unit (PSU): The PSU converts the input voltage into a stable DC supply to provide power for 
the internal functional modules. 

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3  INSTALLATION 
3.1  WARNINGS AND ALERTS 
Radio Frequency Energies 
There  may  be  situations,  particularly  for  workplace  environments  near  high-powered  RF  sources,  where 
recommended limits for safe exposure of human beings to RF  energy could be exceeded. In such  cases, 
restrictive measures or actions may be necessary to ensure the safe use of RF energy. 
High Voltage 
The equipment has been designed and constructed to prevent, as far as reasonably practicable danger. Any 
work  activity  on  or  near  equipment  involving  installation,  operation  or  maintenance  must  be,  as  far  as 
reasonable, free from danger.  
Where there is a risk of damage to electrical systems involving adverse weather, extreme temperatures, wet, 
corrosive or dirty conditions, flammable or explosive atmospheres, the system must be suitably installed to 
prevent danger. 
Protective Earthing 
Equipment  provided  for  the  purpose  of  protecting  individuals  from  electrical  risk  must  be  suitable  for  the 
purpose and properly maintained and used.  
Handling Precautions 
This  covers  a  range  of  activities  including  lifting,  lowering,  pushing,  pulling,  carrying,  moving,  holding  or 
restraining an object, animal or person from the equipment. It also covers activities that require the use of force 
or effort, such as pulling a lever, or operating power tools.  
Where some of the abovementioned activities are required, the equipment must be handled with care to avoid 
being damaged. 
Electrostatic Discharge (ESD) 
Observe  standard  precautions  for  handling  ESD-sensitive  devices.  Assume  that  all  solid-state  electronic 
devices  are  ESD-sensitive.  Ensure  the  use  of  a  grounded  wrist  strap  or  equivalent  while  working  with 
ESD-sensitive devices. Transport, store, and handle ESD-sensitive devices in static-safe environments. 

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3.2  SITE PLANNING CONSIDERATIONS 
3.2.1  SITE PLANNING 
Site Considerations 
Outdoor equipment are designed to be waterproof, rainproof, and with snow protection. Temporary protection 
should  be  taken  when  the  equipment  enclosure  is  opened  for  installation  or  maintenance  in  an  outdoor 
environment. The equipment must not be opened for installation or maintenance in bad weather (e.g. gale, 
storm rainfall, extreme temperatures and high humidity) 
Installation Location 
Mounting surface shall be capable of supporting the weight of the equipment. 
In  order  to  avoid  electromagnetic  interference,  a  proper  mounting  location  must  be  selected  to  minimize 
interference from electromagnetic sources such as large electrical equipment. 
Environmental 
Humidity has an adverse effect on the reliability of the equipment. It is recommended to install the equipment in 
locations having stable temperature and unrestricted air-flow.  
The installation location for the product should be well ventilated. The equipment has been designed to operate 
at the temperature range and humidity level as stated in the product specifications in the datasheet. 
Direct sun light exposure to the equipment should be avoided. Provide additional shelter if necessary. 
Power Supply 
The power supply unit (PSU) provides power to all modules within the equipment. Depending on the product 
variant, it is recommended that the PSU be operated on a dedicated circuit breaker or fused circuit. 
Grounding Requirement 
Verify that the equipment has been well grounded. This includes antennas and all cables connected to the 
system. Ensure lightning protection for the antennas is properly grounded.  
Cable Routing 
Depending on equipment configuration, a variety of types of cables are required. Where applicable, ensure 
cables are properly routed and secured so that they are not damaged. 
Manual Handling 
During transportation and installation, take necessary handling precautions to avoid potential physical injury to 
the installation personnel and the equipment. 

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3.2.2  INSTALLATION CHECKLIST 
  Working  space  available  for  installation  and  maintenance  for  each  mounting  arrangement.  Ensure 
unrestricted airflow. 
  Ensure earth ground point is within reach of the ground wire. 
  Ensure a power source is within reach of the power cord and the power source has sufficient capacity.  
  Where appropriate, ensure unused RF connectors are terminated. 
  Do  not  locate  the  equipment  near  large  transformers  or  motors  that  may  cause  electromagnetic 
interference. 
  Reduce signal loss in feeder cable by minimizing the length and number of RF connections. 
  Ensure VSWR of antennas system < 1.5:1. 
  Ensure equipment will be operated within the stated environment (see datasheet) 
  Observe handling of all cables to prevent damage. Donor antenna should have a narrow beamwidth and 
positioned in line-of-sight (LOS) to the donor BTS site so that the donor signal level is maximized. This 
allows the use of minimum gain to achieve the maximum DL output power. The UL gain is typically set 
lower than or equal to the DL gain to minimize noise interference to the donor BTS 
  Service antennas should be selected based on the type of service area, e.g., indoor antenna for indoor 
application, and panel antenna for outdoor application. 

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3.3  INSTALLATION PROCEDURES 
3.3.1  GOODS INWARDS INSPECTION 
 Verify the number of packages received against the packing list.  
 Check all packages for external damage; report any external damage to the shipping courier. If there is 
damage, a shipping agent should be present before unpacking and inspecting the contents because 
damage during transit is the responsibility of the agent.  
 Open and check each package against the packing list. If any items are missing, contact Comba.  
 Do not remove items from anti-static packing until ready for installation. If damage is discovered at the 
time of installation, contact the shipping agent. 
3.3.2  TOOLS 
See Appendix A for a full list of the recommended tools required for installation and routine maintenance. 
3.3.3  PREPARATION 
  Wall mounting with the masonry bolts supplied, which make use of the outer holes. 
382
280
85
8- 14
530
Figure 4: Mounting Rack Overview 

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3.3.4  WALL MOUNTING  
  Drill four holes on the wall using the position of four holes on the mounting rack as a guide. Fix the 
mounting rack to the wall using four masonry bolts (M10x110mm). 
  Install the Mounting Rack to the wall. 
  Hang the equipment and secure the enclosure to the mounting rack.  
Mounting Rack
Expansion Bolt 
M10X110
Chassis
M8X25,Hexagon 
Head,
Flat Gasket,Pad
Pylons Screw
Wall
Figure 5: PS BDA Wall Mounting 
3.3.5  DRIP-LOOP 
Comba recommends that every horizontal cable entry to the equipment forms a 'U' before its entry to the 
equipment. Water on the cable will drip down at the bottom of the loop and will not accumulate at the equipment 
connectors. 

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3.4  EQUIPMENT CONNECTORS 
3.4.1  PS BDA CONNECTORS 
The PS BDA is designed for all cable entries from the right or left of the enclosure, as shown in the following 
figure.   
OMT LAN ALM1 ALM2 AUX
RUN
PWR
ALM
DT/DL IN MT/DL OUT UL OUT
IN1 OUT1 IN2 OUT2 IN3 OUT3 IN4 OUT4
Figure 6: Equipment Connectors 
Table 1: Equipment Connectors 
Identifier 
Descriptions 
Power1 
Power cable connector for a pre-installed power cord for connection to AC 
(e.g. AC 100-240V 50Hz/60Hz). 
DT /DL IN 
N-Female connector, It is downlink input port and uplink output port for Duplex mode; It is 
downlink input port only for Simplex mode. 
1
 The voltage identification is a variant due to electricity system diversity of global regions. The power cable connector might 
be identified for AC 110V, AC 220V, AC 110V/220V, or DC -48V respectively. Please refer to specific product or contact 
local sales if any doubt. 

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MT/DL OUT 
N-Female connector, It is downlink output port and uplink input port for Duplex mode; It is 
downlink output port only for Simplex mode. 
UL IN 
N-Female connector, It is uplink input port for Simplex mode; It is useless for Duplex 
mode. 
UL OUT 
N-Female connector, It is uplink output port for Simplex mode; It is useless for Duplex 
mode. 
INxx/OUTxx 
Reserved for extension 
ALM1 
Connector for connection to dry contact alarm 1, 2 and 3 
ALM2 
Connector for connection to dry contact alarm 4, 5 and 6. 
AUX 
External alarm 1, 2, 3 and 4. 
LAN 
RJ45 connector for internet connection (Ethernet type only). 
OMT 
RJ45 connector for local connection by WEBOMT 

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3.4.2  PS BDA LED Indicators 
The LED indicators help user to check the equipment status easily.  
 Table 2: LED Indicators 
Identifier 
Colour 
Indication 
PWR 
Green 
Power indicator. ON = power on; OFF = power off.  
RUN 
Green 
Operation indicator, flashes every second to indicate normal operation. 
ALM 
Red 
Alarm indicator. ON = alarm; OFF = no alarm. 
3.4.3  GROUNDING CONNECTION 
Ground Connection 
To ensure safe operation of the product, a ground (earth) connection is required. For single phase AC power 
source, the product must be grounded by connecting the “earth wire” of the power cord to the ground terminal 
of the AC supply. For operating this product with DC power system (such as rectifiers), the product should not 
be connected to power systems that switch open the return lead because the return lead could function as the 
ground (earth) connection for the equipment.  
Protective Ground Connection 
The enclosure must be grounded securely by connecting a copper wire (CSA 16mm2) to the grounding terminal 
on the equipment/rack, and the other end to a protective ground (i.e. building earth point). An internationally 
acceptable color code of the ground connection wire is green/yellow.  
Such a  ground  connection  implements the “Protective  Ground  Connection”, and must be connected to  the 
equipment  at  the  designated  ground  point.  In  general,  do  not  connect  the  supply  before  establishing  an 
adequate ground (earth) connection. 
Construct the ground wire, and use appropriate crimp connectors where necessary. Locate and connect the 
equipment grounding terminal to a protective ground (i.e. building earth point). 
3.4.4  RF CABLE CONNECTION 
Single band PS BDA RF cables connection is as follows:  
 PS BDA MT port  Connects to the feeder cable from service antennas. 
 PS BDA DT port  Connects to the feeder cable from donor antennas. 
3.4.5  ETHERNET CONNECTION 
Connect Ethernet with ‘LAN’ port in the panel, Ethernet type only. 

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3.4.6  DRY CONTACT CABLE CONNECTION 
Below please find the pin definitions of dry contact cables.  
 Table 3: Pin Definition of Dry Contact Cable 
Pin NO. 
Pin 
Input 
ALM1 
1 
CLOSE1 
1 
2 
COM1 
2 
3 
OPEN1 
3 
4 
CLOSE2 
4 
5 
COM2  
5 
6 
OPEN2 
6 
7 
CLOSE3 
7 
8 
COM3  
8 
9 
OPEN3 
9 
ALM2 
1 
CLOSE4 
1 
2 
COM4 
2 
3 
OPEN4 
3 
4 
CLOSE5 
4 
5 
COM5 
5 
6 
OPEN5 
6 
7 
CLOSE5 
7 
8 
COM5 
8 
9 
OPEN5 
9 
AUX 
1 
EXT ALM1 
1 
2 
EXT ALM2 
2 
3 
EXT ALM3 
3 
4 
EXT ALM4 
4 
5 
GND 
5 
6 
GND 
6 
7 
GND 
7 
8 
GND 
8 
9 
NC 
9 

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Dry contact status: 
Main Power Normal/Lost dry contact status:  
Pin definition of ALM and AUX connectors: 
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4  COMMISSIONING  
4.1 PRE-COMMISSIONING TASKS 
After equipment installation, perform the following steps before equipment powering and commissioning: 
 Verify that the expected voltage, current and power levels do not violate any ratings.  
 Visually inspect the power connection within the equipment. Ensure that the power cable is correctly and 
securely connected, including the grounding wire, RF cable and other cables.  
 Check the grounding connection and verify that the ground resistance is less than 5Ω. 
 Test the antenna system and ensure  that the echo loss within working frequency is less  than  -14dB 
(VSWR<1.5).  

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4.2  COMMISSIONING PROCEDURE 
Perform the following procedures for system commissioning. 
Start commissioning guide in WEB GUI
Sub Band Setting
RF Setting
End
Isolation Detection
Site Information Setting
Figure 7: Commissioning Procedure 

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Table 4: Commissioning Task Explanation 
Commissioning Tasks 
Observation 
1.  Site Information Setting 
 Site ID, Dev ID, Dev Info, Longitude , Latitude, Date/time setting 
2.  Sub Band Setting 
 Sub Band Frequency setting. 
3.  Isolation detection 
 Detect isolation of service antenna and donor antenna. 
4.  RF Setting 
 DL_Target and the DL frequency center, the filter bandwidth setting 
and the switch setting. 
5.  Recommended DL and UL 
gain parameters 
 The commissioning guide will provide recommended DL/UL gain 
settings.  
 Users will still need to set all the gains manually in the “Device” pages, 
and the frequencies for all the independent channels in the same 
“Device” pages after the commissioning process is finished. 
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5  WEB GUI 
The PS BDA can be monitored and controlled via the WEB GUI; use the following guide to finish system 
parameter setting and commissioning.  
5.1  WEB GUI CONNECTION 
Step 1: Connect the OMT port to the PC RJ45 port with the supplied RJ45 cable to set up a physical 
connection. 
Step 2: Open a browser (browser IE7.0, IE8.0, Chrome or Firefox, suggested display resolution is 1024×768), 
input Web GUI IP address: 192.168.8.101, click [Enter]. 
NOTE:  
 DHCP and DNS are also available to login to the Web GUI. The domain name is: www.combaomt.com. 
 Advise to clear all the history record of Browse before connecting BDA every time. 
Figure 8: Input IP Address 
Figure 9: Input Domain Name 
Step 3: Input User Name: admin; Password (default password: admin). Click [Log in].  
Figure 10: Input User Name and Password 

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5.2  WEB GUI INTRODUCTION 
After log in, the Web GUI main screen will appear. 
Figure 11: Web GUI Main Screen 
On Comba Web GUI Home Screen, there are four Menu bars:  
[Devices], [Commissioning], [Firmware] and [Management]. 
5.2.1  [DEVICES] 
The [Devices] Screen shows the equipment status, such as PA status, alarm information, etc. 
 Overview Screen  
Figure 12: Overview Screen 
Shows the basic information 
about the PS BDA 
Indicates the 
equipment status 
Indicating 
alarm status 
Click to enable 
/disable alarm 
Indicating 
alarm status 
Click to enable 
/disable alarm 

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400MHz Screen 
This screen is only available for the dual band PS BDA or 800MHz PS BDA. 
Figure 13: 400MHz Screen 1 
Figure 14: 400MHz Screen 2 
5.2.2  [COMMISSIONING] 
A work flow of the commissioning process is shown on [Commissioning] Screen. Click the [Start] button, the 
software will guide you through the commissioning step by step. For details, please refer to chapter 5.3. 
Selecting 
sub band 
Frequency 
information 
RFU 
parameters 
Click to set 
frequency 
information, , 
enable/disable 
RF switch. 
Selecting 
sub band 
Click to set 
bandwidth, 
UL/DL ATT, 
enable/disable 
RF switch. 
Sub band switch 
status 
Center frequency 
of channel 
Channel bandwidth 
Sub band switch 
status 

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Figure 15: [Commissioning] Screen 
5.2.3  [FIRMWARE] 
There are two functions on the [Firmware] bar: [upgrade] and [swap]. [Upgrade] is used to upgrade software, 
and [Swap] is to replace the current firmware version with the previous one. 
Follow the steps shown below figure to upgrade the firmware. 
                                              Figure 16: [Firmware] Screen – MCU Firmware Upgrade 
Step 1: Click to select the 
file for upgrading. 
Step 2: Click to finish the 
software upgrading. 

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Figure 17: [Firmware] Screen – Firmware Swap 
Figure 18: [Firmware] Screen – Module Update 
5.2.4  [MANAGEMENT] 
Other parameters can be configured on  the [Management] Screen. 
Click to swap the firmware 
to the previous version 
Step 2: Click to 
select the file. 
Step 3: Click to finish 
the upgrading. 
Step 1: Check the 
module that needs to be 
updated. 

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Figure 19: [Management] Screen 
Management menu, click 
Enter to each page for 
parameters setting. 

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There are nine function bars list on the left side of the [Mangement] Screen.  
 Inport&Export 
Figure 20: Management – Import & Export 
The parameters that can be imported / exported include sub band, alarm enable, ATT value, RF switch, and DL 
output power. 
This function can help users quickly configure PS BDA parameters. For example, if one PS BDA is finished 
configuration, users can export the parameters and save it as a file on the PC, and then import this file to other 
PS BDAs for faster set up of additional PS BDAs.   
Click to import/export the 
configuration parameters. 

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 IP Setting   
Figure 21: Management – IP Setting 
Note: For remote monitoring, the IP Address must be set correctly based on the location IP of the remote 
connection. If more than one piece of equipment is connected to the public network through the same router, 
the router’s local IP CANNOT be set as 192.168.8.*. 
Configure the IP 
address for remote 
monitoring. 

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 Comm. Setting 
Figure 22: Management – Comm. Setting  
Note: There are 4 available communication types: SMS, PS, SNMP and ETHERNET. You can choose a 
suitable type for remote monitoring. 

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 Security   
Figure 23: Management – Security 

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Click , [Modify Password] window will pop-up.  
Figure 24: Modify Password 
Note: Username cannot be modified.  
 Device Reset 
Figure 25: Management – Device Reset 
Note: Click  , all the parameters and alarms will be reset to factory default value. The Device Reset 
process will last about 2~4 minutes. For PMU monitor reset, users need to re-login to the WEB GUI. 

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 Device Info 
Figure 26: Management – Device Info 
Note: Users can input a maximum of 30 characters in Device Info. 
 Isolation   
Figure 27: Management – Isolation  
Note: This Step is the same as step 5 of [Commissioning]. Users can check isolation again by clicking the 
Check button, the detection range is from 65dB to 125dB. 
Click here to get 
PC time. 
Input device 
information. 

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 RF setting   
Figure 28: Management – RF Setting 
 Alarm Setting 
Figure 29: Management – Alarm Setting 
Click to start 
the alarm test. 

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 Report   
Figure 30: Management – Report  
Note: Click Create to create the report (the report can’t be created in IE browser) and make sure that PDF 
Reader software is installed on the computer. If not, the report will not be visible.  
The device basic information, an overview of RF information and sub-band RF information are included in this 
report. Please refer to appendix D for an example of device report. 
  Alarm Log 
Figure 31: Management – Alarm Log 
Click to export alarm 
log or clear alarm log 

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 Clear History Alarm 
Figure 32: Management – Clear History Alarm 
Click to clear history alarm  

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5.3  COMMISSIONING PROCEDURE 
To complete the installation and commissioning, users need to follow the steps below.  
Step 1: Click the Menu bar [Commissioning] on home screen, a work flow will be displayed. 
Figure 33: Commissioning Procedure – Start 
Step 2: Click   to start the process. 
Figure 34: Commissioning Procedure – Site Info. Setting 
Step 3: Click , to set the site information. 

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Figure 35: Device Information Setting 
It is mainly used to record device location and Date/Time provides a time reference. Clicking the Config Value 
of Date/Time will update the Date/Time automatically. 
Step 4 : Click  to enter to Sub Band Setting. 
Reminder:  
 Make sure the frequency of sub-bands match the actual frequency of filters, or BDA cannot work normally. 
 If the frequency is within [450MHz,470MHz], the bandwidth between DL Freq Low and DL Freq High can 
be adjusted from 0.2 to 5MHz only. If the frequency is within[ 470,512], the bandwidth between DL Freq 
Low and DL Freq High can be adjusted from 0.2-3MHz. 
 The frequency edges of two sub bands can be overlap, but they cannot be cross-contained. 
 The channel center frequency must be within the frequency range of its relative sub-band, if it is not within 
the range, the system will show a reminder window to show the setting unsuccessful. 
 If the sub band is off, all the channels belong to the sub band are auto set to off. 
 The procedure of sub band switch on: sub band 1 is first, and then 2, 3, 4. The procedure of sub band 
switch off: sub band 4 is first, and then 3, 2, 1. And the isolation use sub band 1 to test, so make sure sub 
band 1 is always on when BDA is working. 
NOTE:  Make  sure  the  device  is  connected  with  appropriate  donor  and  service  antennas  before 
proceeding to step 5. 

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Step 5: Click   to enter to Isolation Detection Screen. 
Figure 36: Commissioning Procedure – Isolation Detection 
  Click   to start Isolation Detecting, then a [Confirm] window will pop-up. 
  Click   to continue. If isolation detection passes, the process will go to the RF Settiing Screen shown 
as Figure 39. If failed, a Tips window will pop-up, users need to check whether the system isolation is 
adequate. 
NOTE: At the end of the first frequency band commissioning, users can start other frequency band 
commissioning.   
Figure 37: Commissioning Procedure – Isolation Detection Confirm 
Figure 38: Commissioning Procedure – Isolation Detection Failed 

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                                    Figure 39: Commissioning Procedure – Isolation Detection Finish 
Step 5: RF Setting Screen for setting the center frequency.  
Figure 40: Commissioning Procedure – Center Frequency Setting 
Figure 41: Commissioning Procedure – Channel Number Setting 
Step 1: Click to 
open the 
parameter setting 
page. 
Step 2: Input the 
desired value. 
Step 3: Click to 
finish the setting. 
Step 4: Click next to 
continue RF setting. 
Step 1: Click to 
open the 
parameter setting 
page. 
Step 2: Input the 
desired value. 

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Step 7: Click    to finish the commissioning. In this window, a summary of device setting is shown.  
Figure 42: Commissioning Procedure – Finish 
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6  MAINTENANCE 
The PS BDA is designed for trouble-free operation and generally does not need maintenance. Maintenance 
activities should only be carried out by trained personnel. 
Periodic inspection of the repeater equipment(s) is recommended, the recommended tasks includes: 
 Verify the direction and position of antennas. Re-align if necessary. 
 Make sure the cable connector and sealing on the RF cable connectors are not damaged.  
 Verify lightning and grounding protection is in good condition. 
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7  APPENDICES 
7.1  APPENDIX A: TOOLS 
The following are the recommended list of tools for new installation and routine maintenance. 
  Slotted Screwdriver 
  Philips Screwdriver 
  Ring Spanner (Assorted size: 12~20mm) 
  Electrically operated drill and masonry drill bits 12mm 
  Anti-static Wrist Strap 
  Side Cutter 
  Frequency Counter (e.g. FLUKE PM6685R) 
  RF Power Meter (e.g. Bird 5000) 

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7.2  APPENDIX  B:  DECLARATION  OF  HARMFUL  SUBSTANCES  AND 
CONTENT  
Product Name: Public Safety BDA 
Model: RX-4122 
Harmful substance and content of this product as below table shown: 
Part Name 
Harmful Substance 
Pb 
Hg 
Cd 
Cr (VI) 
PBB 
PBDE 
A 
× 
○ 
○ 
○ 
○ 
○ 
B 
× 
○ 
○ 
○ 
○ 
○ 
Note: Above table complies with SJ/T 11364.   
○:  Indicates  that  the  harmful  substance  content  in  all  homogeneous  materials  for  corresponding  part  is  under  the  limited 
requirement of GB/T 26572. 
×: Indicates that the harmful substance content in at least one single  homogeneous material  for the corresponding part exceeds the 
limited requirement of GB/T 26572. 
Remark: The content of the parts marked with “×”above exceeds the requirement as there is still no mature alternative 
technologies to achieve the replacement of poisonous and harmful materials or elements. 

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7.3  APPENDIX F: RMA (RETURN MATERIAL AUTHORIZATION) 
End of Section 

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