Continental Automotive Technologies S120123 Tire Pressure Monitoring Transmitter User Manual Func TG1B USA
Continental Automotive GmbH Tire Pressure Monitoring Transmitter Func TG1B USA
User Manual

SIEMENS VDO Automotive    SV C BC P2 
 FCC ID:KR5S120123  IC:267T-S120123 
File: Func_TG1B_USA.doc    1 of 6 
 User Manual / Functional Description 
 of the 
Siemens VDO 
 Tire Pressure Monitoring transmitter 
Generation 1B 
Type  
S120123  

SIEMENS VDO Automotive    SV C BC P2 
 FCC ID:KR5S120123  IC:267T-S120123 
File: Func_TG1B_USA.doc    2 of 6 
General description 
The tire pressure monitoring system (referred to as TireGuard) consists of the 
following units : 
- Tire guard transmitter type S120123 which includes an integrated pressure, 
temperature and acceleration sensor and a 315 MHz RF transmitter. 
- RF receiver unit which includes a 315 MHz receiver (not described in this 
document) 
The TireGuard system monitors a vehicle's tire pressure whilst driving or 
stationary. An electronic unit (wheel unit) inside each tire, mounted to the valve 
stem, periodically measures the actual tire pressure. By means of RF 
communication, this pressure information is transmitted to the RF 
receiver/decoder. 
When the vehicle starts moving, the TireGuard transmitter enters the driving 
mode. It measures and transmits RF burst 4 times per minute up to 30 bursts. 
The telegram length is approximately 30ms. After this period the transmitter 
measures and transmits data every minute.  The transmitter will remain in driving 
mode for a period of 10 minutes after the vehicle is stopped.  
If, during any measurement period in driving mode, the pressure leakage is 
detected (difference compared to the last transmitted pressure value), a re-
measure will occur after 5s taking in account the latest pressure value emitted as 
reference value. If the pressure continues changing, an additional transmission 
will be sent. 
For normal transmission the wheel must be rotating and the device must be 
pressurized. For factory testing, installation testing, ect., the device has been 
designed to be activated also by a 125kHz signal.  For homologation testing one 
sample was modified for CW emission, that last about 2 min. after activation with 
LF. 

SIEMENS VDO Automotive    SV C BC P2 
 FCC ID:KR5S120123  IC:267T-S120123 
File: Func_TG1B_USA.doc    3 of 6 
Technical description 
Carrier frequency:       315 MHz 
Frequency shift:        ± 45 kHz 
Number of channels:      1 
Duty cycle:        < 0.1% 
Type of modulation:       Frequency Shift Keying (FSK) 
Rated Output Power:      < 10 mW 
Antenna:          integral 
Voltage supply:        1 Lithium battery 3V (CR2450) 
Voltage supply range :      2.1 up to 3.2V 

SIEMENS VDO Automotive    SV C BC P2 
 FCC ID:KR5S120123  IC:267T-S120123 
File: Func_TG1B_USA.doc    4 of 6 
Block diagram 
The block diagram below shows the main electronic units of the TireGuard 
transmitter: 
3V
LITHIUM
BATTERY
Learning coil
RF CIRCUIT
VALVE
Pressure,
temperature,
acceleration
sensor and
µcontroller

SIEMENS VDO Automotive    SV C BC P2 
 FCC ID:KR5S120123  IC:267T-S120123 
File: Func_TG1B_USA.doc    5 of 6 
Label design 
Siemens VDO 
S120123 
IC: 267T-S120123           
FCC ID:KR5S120123 

SIEMENS VDO Automotive    SV C BC P2 
 FCC ID:KR5S120123  IC:267T-S120123 
File: Func_TG1B_USA.doc    6 of 6 
User manual information 
IC: 267T-S120123           
FCC ID:KR5S120123 
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. 
NOTE 
Changes or modifications not expressly approved by the manufacturer could void 
the user´s authority to operate the equipment.