Continental Automotive Technologies 5WK49127 Key User Manual
Continental Automotive GmbH Key
User Manual
Annex No.5 
Technical Description 
Key: 5WK4 9127 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49127                             FCC ID:KR55WK49127 
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 User Manual  
of the  
Siemens VDO 
 Remote Control System  
Type: 
 5WK4 9125 
5WK4 9126 
5WK4 9127 
5WK4 9128 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49127                             FCC ID:KR55WK49127 
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General description of the RF transmitter PL2 TX 
The RF remote control system consists of a RF transmitter and a RF receiver 
mounted within the control unit. The RF transmitter is mechanically integrated 
in the head of the key. This transmitter is used to transmit an information for 
locking or unlocking the vehicle by an unidirectional RF transmission line for 
normal remote operation by pressing a button. 
In general the following functions are provided: 
-  Lock the car 
-  Unlock the car 
-  Unlock the trunk of the car 
Power supply 
The transmitter is provided with 1 Lithium accumulator (VL 2020) that gives a 
power supply of +3V.  
Buttons 
There are three buttons which enable to lock and unlock the doors and to 
unlock the trunk. 
During activation, the button is forced to the ground via a “pull-up” within the 
microcontroller. 
Typical usage pattern (for Europe only) 
10 lock/unlock operations in 24 hours with typical transmission duration of 2 seconds 
→ 0,42 lock/unlock operations with one hour 
Transmitter ON  0.84    seconds / hour 
Transmitter OFF  3599.16  seconds / hour 
Duty Cycle: TON / T (ON+OFF)  x 100% = 0.84 / 3,600 x 100 % = 0.02% 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49127                             FCC ID:KR55WK49127 
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Block diagrams of the transmitter 
Button's PLL Transmitter
IC
9,84375 MHz
Crystal
125 kHz
LF Circuit
(L/C)
315 MHz
Loop Antenna
µC for LF communication /
RF - transmittion
Power Supply
2,2 to 3,3 V
µC reference frequency
616,54kHz
Tx, RF data
4,807 kBit/sec
315 MHz
Button's PLL Transmitter
IC
13,5687 MHz
Crystal
125 kHz
LF Circuit
(L/C)
µC for LF communication /
RF - transmittion
Power Supply
2,2 to 3,3 V
µC reference frequency
847,5kHz
Tx, RF data
5,3 kBit/sec
434,2
MHz
434 MHz
Loop Antenna

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49127                             FCC ID:KR55WK49127 
I:\POSTZULA\BMW\PL2_TX-ext\Technische_Doku_doc\Func_PL2ext_TX.doc    Page 4 of 6
Button's PLL Transmitter
IC
13,5687 MHz
Crystal
125 kHz
LF Circuit
(L/C)
µC for LF communication /
RF - transmittion
Power Supply
2,2 to 3,3 V
µC reference frequency
847,5kHz
Tx, RF data
5,3 kBit/sec
868,4
MHz
868,4 MHz
Loop Antenna

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49127                             FCC ID:KR55WK49127 
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Variants 
Model Description 
5WK4 9125 868.4MHz variant for Europe 
5WK4 9126 434.2MHz variant for Europe 
5WK4 9127 315MHz variant for USA 
5WK4 9128 315MHz variant reduced power for Japan 
Technical Data  
Carrier frequency model 5WK4 9125:    868.4 MHz ± 0.05% 
Carrier frequency model 5WK4 9126:    434.2 MHz ± 0.05% 
Carrier frequency model 5WK4 9127:    315.0 MHz ± 0.05% 
Carrier frequency model 5WK4 9128:    315 MHz ± 0.05% 
Output power model 5KW4 9125/6/7:    < 10 mW 
Field strength model 5WK49128:      < 500µV/m @ 3m 
Type of modulation model 5KW4 9125/6/7:   FSK  
Type of modulation model 5KW4 9128:     ASK  
Method of frequency generation:   PLL 
Number of channels:        1 
Power supply:          accumulator (VL 2020) 
- Nominal voltage:        3 V 
- Lowest voltage:        2, 1 V 
- Highest voltage:        3, 3 V 
Type of accumulator:    lithium 
Transmission range:        <10 m  
Type of RF-antenna:        Loop antenna 
Length of RF-antenna:        34 mm 

Siemens VDO Automotive AG    SV C BC P2 RF 
 IC: 267T-5WK49127                             FCC ID:KR55WK49127 
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Label design 
Europe: (434 MHz)       Europe: (868 MHz) 
Siemens VDO    Siemens VDO   
5WK4 9126          5WK4 9125 
Japan: (315 MHz) 
Siemens VDO 
5WK4 9128 
USA/CAN: (315 MHz) 
Siemens VDO 
5WK49127 
IC: 267T-5WK49127           
FCC ID:KR55WK49127 
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.