RJ21 50-pin connectors aggregate multiple SIP trunk lines or analog telephone lines in VoIP gateways and PBX systems, where a single connector terminates 25 pairs for connection to PSTN or IP telephony equipment.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1-25 | Tip 1-25 | Line tip conductors 1 to 25 | BUS |
| 26-50 | Ring 1-25 | Line ring conductors 1 to 25 | BUS |
RJ21 50-pin connectors aggregate multiple SIP trunk lines or analog telephone lines in VoIP gateways and PBX systems, where a single connector terminates 25 pairs for connection to PSTN or IP telephony equipment.