Continental Automotive Technologies 5WK49046 Remote Control for Vehicle Access User Manual
Continental Automotive GmbH Remote Control for Vehicle Access
user manual
Annex No.5 
Technical Description 
Key 5WK4 9046 

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 1 of 7 
 User Manual  
of the 
Siemens VDO 
Remote Control Transmitter 
Type: 
Designkey 

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 2 of 7 
General description of the Designkey  "Keyless Go" 
The Designkey incorporates two main functional features. 
   1.   RF remote control system : activation by button press  
2.   Keyless go system             : activation by an external LF-signal source. 
In both activation modes the Designkey answers with the available RF (radio 
frequency) interface. For remote control function additionally IR (infra red) 
communication is in use. 
In regular application the RF receiver is located within the control unit which is 
mounted in the car interior. The Designkey RF transmitter antenna is 
mechanically integrated in the key head. The RF transmitter is used to 
transmit different information by a unidirectional transmission line to the RF 
receiver within the control unit. 
In regular application the following functions are provided by the Designkey : 
-  Lock the car 
-  Unlock the car 
-  Unlock the trunk of the car 
- Driver authentication ( Keyless Go ) 
- Panic activation ( USA only ) 
Power supply 
The transmitter is provided with 2 Lithium batteries (CR 2025) that both gives 
a power supply of +3V. 
Buttons 
There are three buttons which enable to lock and unlock the doors and to 
unlock the trunk and an extra button in case of required panic function (USA 
only). 
During activation, by button press the microcontroller port is forced to ground 
via a “pull-up” within the microcontroller. 

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 3 of 7 
Typical usage pattern (for Europe only) 
96 lock/unlock operations in 24 hours with typical transmission duration of 0.8 
seconds 
→ 4 lock/unlock operations with one hour 
Transmitter ON  3.2    seconds / hour 
Transmitter OFF  3,596.8  seconds / hour 
Duty Cycle: TON / T (ON+OFF)  x 100% = 3.2 / 3,600 x 100 % = 0.08 % 

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 4 of 7 
Block diagrams of the transmitter 
µC for   
        RF Tx    and  
IR RxTx  
data transmission 
µC for button 
and 
LF communication 
Button's
Keyless Go -
Control Unit
IR- Transmitter 
IR - Receiver 
RF transmitter
LED
Power  management
Manchester 
coded
Battery A
Battery B
standard 
µC interface 
  9,84375 MHz Crystal for 315,0 MHz  
13,5687   MHz Crystal for 433.92 MHz  
Crystal 

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 5 of 7 
Variants 
Model Description 
5WK4 9045 433.92 MHz variant for Europe 
5WK4 9046  315.00 MHz variant for USA 
Technical Data  
Carrier frequency model 5WK4 9045:    433.92 MHz ± 0.05% 
Carrier frequency model 5WK4 9046:    315.00 MHz ± 0.05% 
Output power model 5KW49045       :    < 10 mW 
Field strength model 5WK49046       :     < 6000µV/m @ 3m 
Type of modulation:          FSK  
Method of frequency generation:   PLL 
Number of channels:        1 
Power supply:     battery (2x CR 2025) 
Type of battery:          lithium 
Transmission range:        <10 m  
NOTE: 
Changes or modifications not expressly approved by the manufacturer could 
void the users authority to operate the equipment.  

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 6 of 7 
Label design 
Europe: (433.92 MHz)       USA/CAN: (315 MHz) 
Siemens VDO 
5WK4 9045 
 Siemens VDO 
  5WK4 9046 
 IC: 267T-5WK4 9046 
  FCC ID: KR55WK49046 
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. 

Siemens VDO Automotive AG    SV C BC P2 RF TG 
 IC: 267T-5WK49046          FCC ID:KR55WK49046 
I:\POSTZULA\MB_DC\DesignKey\Original_Doku\Func_Designkey.doc Page 7 of 7 
Homologation functionality 
For homologation use the Designkey samples are programmed with a special 
software which allows to set the RF transmission in following modes : 
1 ) Constant carrier high frequency 
2 ) Constant carrier low  frequency 
3 )   1 kBit Modulation 
4 ) 10 kBit Modulation 
The following diagram shows how to activate the different homologation modes. 
OFF
Constant
LOW
FREQ.
(LED Blink
200ms)
Constant
HIGH
FREQ.
(LED Blink
200ms)
Modulated
1kbit/s
(LED Blink
20ms)
Modulated
10
kbit/s
(LED Blink
50ms)
trunk button
any button
open button
close or panic or trunk
button
close button
close button
 trunk or open or panic
button
any button
panic button
open button
