| Pin | Type | Description / Signal type | Connection / Measuring notes
 | 
|---|
| 1 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 2 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 3 |  | Not used |  | 
|  |  |  | 
| 4 |  | Not used |  | 
|  |  |  | 
| 5 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 6 |  | Not used |  | 
|  |  |  | 
| 7 |  | Not used |  | 
|  |  |  | 
| 8 |  | Not used |  | 
|  |  |  | 
| 9 | M | Shield | Shield Navigation | 
|  |  |  | 
| 10 | A | Communication link RXD | Navigation control unit | 
|  |  |  | 
| 11 | A | Communication link TXD | Eject box | 
|  |  |  | 
| 12 | E | Voltage supply terminal R | Fuse F46 | 
|  |  |  | 
| 13 | E/A | I-bus signal line | I-bus connector Telephone connector | 
|  |  |  | 
| 14 |  | Not used |  | 
|  |  |  | 
| 15 |  | Not used |  | 
|  |  |  | 
| 16 |  | Not used |  | 
|  |  |  | 
| 17 | A | Negative activation, front loudspeaker | Voice input Amplifier Front loudspeaker | 
|  |  |  | 
| 18 | A | Positive activation, front loudspeaker | Voice input Amplifier Front loudspeaker | 
|  |  |  | 
| 19 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 20 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 21 |  | Not used |  | 
|  |  |  | 
| 22 |  | Not used |  | 
|  |  |  | 
| 23 |  | Not used |  | 
|  |  |  | 
| 24 | M | Ground | Ground connector | 
|  |  |  | 
| 25 | E | Voltage supply terminal 30 | Fuse F70 | 
|  |  |  | 
| 26 |  | Not used |  | 
|  |  |  | 
| 27 |  | Not used |  | 
|  |  |  | 
| 28 | A | Data cable | Navigation control unit | 
|  |  |  | 
| 29 | A | Telephone mute signal | Radio | 
|  |  |  | 
| 30 |  | Not used |  | 
|  |  |  | 
| 31 | E | Voltage supply terminal 30 | Fuse F70 | 
|  |  |  | 
| 32 | E | Voltage supply terminal 30 | Fuse F70 | 
|  |  |  | 
| 33 | M | Ground | Ground connector | 
|  |  |  | 
| 34 | M | Ground | Ground connector | 
|  |  |  | 
| 35 |  | Not used |  | 
|  |  |  | 
| 36 |  | Not used |  | 
|  |  |  | 
| 37 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 38 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 39 | M | Shield | Shield | 
|  |  |  | 
| 40 |  | Not used |  | 
|  |  |  | 
| 41 |  | Not used |  | 
|  |  |  | 
| 42 | M | Ground | Ground connector | 
|  |  |  | 
| 43 | E | Voltage supply terminal 30 | Fuse F70 | 
|  |  |  | 
| 44 | M | Not used |  | 
|  |  |  | 
| 45 | M | Not used |  | 
|  |  |  | 
| 46 | A | Data cable | Navigation control unit | 
|  |  |  | 
| 47 | A | Telephone ON signal | Voice input Amplifier | 
|  |  |  | 
| 48 | A | Siemens internal | Eject box Tandem telephone | 
|  |  |  | 
| 49 |  | Not used |  | 
|  |  |  | 
| 50 |  | Not used |  | 
|  |  |  | 
| 51 |  | Not used |  | 
|  |  |  | 
| 52 | A | Negative input signal, microphone | Voice input Microphone | 
|  |  |  | 
| 53 | M | Shield | Shield Microphone | 
|  |  |  | 
| 54 | A | Positive input signal, microphone | Voice input Microphone | 
|  |  |  |