| Pin | Type | Description / Signal type | Connection /
Measuring notes |
|---|
| 1 | E/A | Telephone, internal | Interface |
| | | |
| 2 | E/A | Telephone, internal | Interface |
| | | |
| 3 | M | Ground | Ground splice |
| | | |
| 4 | E | Terminal 30 voltage supply | Fuse F74 |
| | | |
| 5 | E | Voltage supply terminal R | K3 Unloader relay, terminal R |
| | | |
| 6 | E/A | Telephone, internal | Interface |
| | | |
| 7 | E/A | Telephone, internal | Interface |
| | | |
| 8 | E/A | Telephone, internal | Interface |
| | | |
| 9 | | Not used | |
| | | |
| 10 | A | Telephone mute signal | Voice input Radio |
| | | |
| 11 | E/A | Telephone, internal | Interface |
| | | |
| 12 | E/A | Telephone, internal | Interface |
| | | |
| 13 | E/A | Telephone, internal | Interface |
| | | |
| 14 | A | Negative input signal, microphone | Voice input Microphone |
| | | |
| 15 | A | Positive input signal, microphone | Voice input Microphone |
| | | |
| 16 | | Not used | |
| | | |
| 17 | | Not used | |
| | | |
| 18 | E/A | Telephone, internal | Interface |
| | | |
| 19 | A | Front loudspeaker voltage control | Voice input Amplifier Front loudspeaker |
| | | |
| 20 | M | Shield | Shield Microphone |
| | | |
| 21 | | Not used | |
| | | |
| 22 | | Not used | |
| | | |
| 23 | M | Shield | Shield |
| | | |
| 24 | M | Ground | Interface |
| | | |
| 25 | A | Front loudspeaker ground control | Voice input Amplifier Front loudspeaker |
| | | |