RJ12 Pinout
Six-position, six-contact (6P6C) modular jack wiring all six contacts.
Overview
RJ12 (often used interchangeably with RJ25) is a 6P6C registered jack - six positions with all six contacts loaded. It shares the RJ11 body but populates every contact.
All three pairs are available, so a 6P6C connector can carry up to three telephone lines or proprietary signaling in key/PBX systems.
Pinout
| Pin | Name | Function | Description |
|---|---|---|---|
| 1 | Line 3 Ring (blue) | PAIR / VIDEO | Third pair Ring |
| 2 | Line 2 Tip (black) | PAIR | Second pair Tip |
| 3 | Line 1 Tip (green) | VIDEO | Primary line Tip |
| 4 | Line 1 Ring (red) | VIDEO | Primary line Ring |
| 5 | Line 2 Ring (yellow) | PAIR | Second pair Ring |
| 6 | Line 3 Tip (white) | PAIR | Third pair Tip |
Notes
- Pairs are symmetric about the center: pair 1 on 3/4, pair 2 on 2/5, pair 3 on 1/6.
- Color codes vary; USOC two-line order shown.
Reference: Wikipedia - Registered jack (6P6C / RJ12/RJ25)· verified 2026-06-27