Siemens C25 & S25 pinouts

Pin Name Function in/out
1 GND Ground  
2 SELF-SERVICE Recognition/control battery charger in/out
3 LOAD Charging voltage in
4 BATTERY Battery (S25 only) out
5 DATA OUT Data sent (S25 only) out
6 DATA IN Data received (S25 only) in
7 Z_CLK Recognition/control accessories  
8 Z_DATA Recognition/control accessories  
9 MICG Ground for microphone in
10 MIC Microphone input  
11 AUD Loudspeaker out
12 AUDG Ground for external speaker  

 

  • The telephone detects the attached battery charger via Pin 2 and controls this via a PCM signal at the same pin.
  • Accessories are detected via Pins 7 and 8
  • The Headset identifies itself through HIGH/LOW instead of HIGH/HIGH