| Pin | Type | Description / Signal type | Connection /
Measuring notes |
|---|
| 1 | E | Terminal 30 | Fuse F39 |
| | | |
| 2 | | Not used | |
| | | |
| 3 | | Not used | |
| | | |
| 4 | | Not used | |
| | | |
| 5 | | Not used | |
| | | |
| 6 | | Not used | |
| | | |
| 7 | | Not used | |
| | | |
| 8 | A | Negative activation Microphone | Microphone, hands-free/voice input |
| | | |
| 9 | A | Positive activation Microphone | Microphone, hands-free/voice input |
| | | |
| 10 | E | Negative activation Microphone | Basic interface telephone |
| | | |
| 11 | E | Positive activation Microphone | Basic interface telephone |
| | | |
| 12 | A | Signal, telephone AF - | Radio control unit |
| | | |
| 13 | A | Signal, telephone AF + | Radio control unit |
| | | |
| 14 | M | Ground | Ground point |
| | | |
| 15 | | Not used | |
| | | |
| 16 | | Not used | |
| | | |
| 17 | | Not used | |
| | | |
| 18 | A | Signal Telephone on | Radio control unit |
| | | |
| 19 | | Not used | |
| | | |
| 20 | | Not used | |
| | | |
| 21 | A/E | K-bus signal | K-bus connector |
| | | |
| 22 | A | Signal, telephone mute | Connector X4553 MUTE |
| | | |
| 23 | E | Signal Telephone on | Basic interface telephone |
| | | |
| 24 | E | Terminal R | Fuse F7 |
| | | |
| 25 | E | Signal, telephone AF - | Basic interface telephone |
| | | |
| 26 | E | Signal, telephone AF + | Basic interface telephone |
| | | |