Continental Automotive Technologies 5WK49244 Radio frequency transmitter User Manual
Continental Automotive GmbH Radio frequency transmitter
User manual

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49244                                                                 FCC ID:KR55WK49244 
I:\POSTZULA\EuCD\CID_Multichannel\Technische_Doku_doc\Func_Jaguar_CID_X150_315MHz_HP_MC.doc 
Page 1 of 4 
 User Manual  
of the  
Siemens VDO 
 Radio Frequency Transmitter  
type 5WK4 9244 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49244                                                                 FCC ID:KR55WK49244 
I:\POSTZULA\EuCD\CID_Multichannel\Technische_Doku_doc\Func_Jaguar_CID_X150_315MHz_HP_MC.doc 
Page 2 of 4 
1. GENERAL DESCRIPTION OF THE RF TRANSMITTER  
The RF remote control system consists of a RF transmitter and a LF 
receiver mounted on a control unit. The RF transmitter is mechanically 
integrated in the head of the key. This transmitter is used to transmit 
information for locking or unlocking the vehicle by a unidirectional RF 
transmission line for normal remote operation by pressing a button. Also is 
implemented the function of the Immobilizer in the transmitter with a 
bidirectional LF – transmission (passive). 
In general the following functions are provided: 
- Lock the car 
- Unlock the car 
- Unlock the boot lid of the car 
- Approach light 
- Panic alarm   
- Immobilizer 
2. POWER SUPPLY 
 The transmitter is provided with 1 lithium battery (CR 2032) that gives a 
power supply of +3V.  
3. BUTTONS 
 There are five buttons with following functions: 
 Action:  Usage: 
Central locking 
Activation of Alarm system 
Pressing the lock button 
Deactivation of Panic Alarm 
Pressing the lock button for 1,5 sec. Comfort closing 
Central unlocking 
Deactivation of Alarm system 
Pressing the unlock button 
Deactivation of Panic Alarm 
Pressing the unlock button for 1,5 sec. Comfort opening 
Pressing the unlock button twice within 10 sec. Two-step unlocking 
De-/activation of Approach Light 
Deactivation of Panic Alarm 
Pressing the approach light button 
Pressing the approach light button for 1,5 sec.   
Unlocking of Boot lid Pressing the boot lid button Deactivation of Panic Alarm 
Activation of Panic Alarm Pressing the panic button for 3 sec or pressing 
it twice within 3 sec. Deactivation of Panic Alarm 
During activation, the button is forced to the ground via a “pull-up” within 
the microcontroller. 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49244                                                                 FCC ID:KR55WK49244 
I:\POSTZULA\EuCD\CID_Multichannel\Technische_Doku_doc\Func_Jaguar_CID_X150_315MHz_HP_MC.doc 
Page 3 of 4 
4. BLOCK DIAGRAM OF THE TRANSMITTER 
Circuit description: 
The central elements of the Transmitter are the controller and LF receiver IC 
PCF 7953ATJ and the synthesizer PLL – RF-Transmitter PCF7900 from 
Philips 
Controller PCF 7953  
The PCF7953 is a high performance single chip Security Transponder, 
Keyless Entry and RISC Controller, ideally suited for automotive applications 
with combined vehicle Immobilization and Keyless Entry/Start functions. 
Unless other products, the device comes with a package integrated 
Transponder LF coil used in combination with the Security Transponder or 
and Keyless Entry function. The Security Transponder features secure 
contactless authentication, employing a Secret Key and a random number in 
order to cipher any communication between the device and the basestation. 
The basic transponder operation is emulated utilizing the on-chip RISC and 
may feature a customized operation or may use the built in Transponder 
Library functions, that offer HT2 compatible operation (e.g. PCF7936). Neither 
other external components nor an additional battery supply is needed. 
Keyless Entry operation incorporates a high sensitive 3D LF front-end that 
offers low power LF Wake-Up detection and LF data communication. To 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49244                                                                 FCC ID:KR55WK49244 
I:\POSTZULA\EuCD\CID_Multichannel\Technische_Doku_doc\Func_Jaguar_CID_X150_315MHz_HP_MC.doc 
Page 4 of 4 
support key localization, the received LF field strength can be evaluated. 
Device operation is controlled by a ROM or E-ROM programmable (FLASH 
like features) low power 8 Bit RISC controller. The RISC employs a 2 stage 
pipeline architecture in order to execute an instruction in a single clock cycle. 
Device timing is derived from an on-chip low tolerance RC Oscillator and 
programmable system clock, with a frequency up to 2 MHz. The system clock 
may also be derived from the transponder interface (LF Field clock) or an 
external clock source. 17 general purpose I/Os are provided for command 
buttons, LED, or control of an external RF transmitter/transceiver circuitry. 
Device authentication or rolling code generation may employ the hardwired 
Calculation Unit that can operate in standard HT2 (48 bit Secret Key) or HT2-
Enhanced (64 bit Secret key) mode. In addition an AES compliant operation 
with a 128 bit Secret Key is provided. Depending on the operation mode, the 
RISC is powered from the external battery or derives its power supply by 
inductive coupling (transponder mode) to the LF Field generated by the 
basestation. The PCF7953ATJ incorporates an advanced power management 
that supports battery voltage measurement and optional battery charging from 
the LF Field. The device comes in a 36 pin Leaded Stick Package (LSP). The 
device is available as E-ROM (FLASH like Features) and in-circuit 
programming and debugging is supported. 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49244                                                                 FCC ID:KR55WK49244 
I:\POSTZULA\EuCD\CID_Multichannel\Technische_Doku_doc\Func_Jaguar_CID_X150_315MHz_HP_MC.doc 
Page 5 of 4 
Synthesizer PLL –RF Transmitter PCF7900 
The UHF ASK/FSK Fractional-N Transmitter IC (FraNTIC) is a single-chip 
Fractional-N based Phase Locked Loop (PLL) frequency synthesizer and a 
power amplifier to drive an external antenna, utilizing a sophisticated CMOS 
process. FRANTIC is especially designed for use in the ISM frequency bands 
(315/434/868/915 MHz). Fine-tuning of the reference oscillator by means of 
fractional-N synthesis allows compensation of manufacturing tolerances of the 
crystal. The device also provides an adjustable output power. FRANTIC can 
be used for both ASK and FSK modulation with data rates up to 40 kBit/s. 
Due to the high level of integration, only few external components are needed 
to build up a complete transmitter.  
General Function: 
The function of the key was mainly realized by the use of two integrated 
circuits from Philips. The PCF7953 contains the LF Front-end where the three 
receiving tanks are connected. One of these tanks is inside the housing of the 
PCF7953ATJ and also used for transponder communication. By the use of a 
capacitor these coils are tuned to a 125 kHz resonant circuit. LF Front-end 
and state machine of the PCF7953 are always supplied by the battery. If 
these part of the PCF7953 detects a 125 kHz Manchester coded LF-signal 
which contains a valid Wake Up Pattern (WUP), the microprocessor starts the 
execution of the application program. The WUP is unique for each KV-System 
and is used for PASE communication with the car. The second possibility to 
wake up the microprocessor is a button press. 
Most of the LF requests to the PK are answered by sending a RF-Telegram. 
The PCF7900 is a synthesizer PLL Transmitter and offers the capabilities to 
send ASK or FSK modulated RF telegrams on up to four channels. The RF 
answer to LF requests is FSK modulated with 8kbit/s data rate. The RF 
answer to a button press is also FSK modulated with 8kbit/s data rate. The 
wake up pattern which is send after a button press to wake up the receiver is 
ASK modulated. 
The PCF7953 has an internal RC oscillator. This kind of oscillator is not 
precise enough for generating answer- or baud-rate-timings of RF answers. 
Therefore the PCF7953 switch on the reference oscillator of the PLL, which 
deliver a quartz stable timer clock. 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49244                                                                 FCC ID:KR55WK49244 
I:\POSTZULA\EuCD\CID_Multichannel\Technische_Doku_doc\Func_Jaguar_CID_X150_315MHz_HP_MC.doc 
Page 6 of 4 
5. TECHNICAL DATA  
Center frequency channel 1:    314.703 MHz ± 30ppm 
Center frequency channel 2:    315.000 MHz ± 30ppm 
Center frequency channel 3:    315.297 MHz ± 30ppm 
Output power:        < 75.6dBµV/m 
Type of modulation:      ASK for WUP; FSK ± 20 kHz for data 
Method of frequency generation:  Synthesizer PLL 
Number of channels:      3 
Power supply:        battery (CR 2032) 
Type of battery:    lithium 
Transmission range:      < 50 m  
NOTE: 
Changes or modifications not expressly approved by the manufacturer 
could void the user's authority to operate the equipment.  
7. LABEL DESIGN CANADA, MEXICO, USA 
Siemens VDO 
5WK49244 
IC: 267T-5WK49244 
FCC ID:KR55WK49244 
Entry Owners Manual, Canada, USA: 
NOTE 
This device complies with part 15 of the FCC Rules and RSS-210. 
Operation is subject to the following two conditions: (1) This device may not 
cause harmful interference, and (2) this device must accept interference 
received, including interference that may cause undesired operation. 
COUTION 
Changes or modifications not expressly approved by the manufacturer 
could avoid the user's authority to operate the equipment.