---
tags:
  - resource
created: 2026-05-29 18:26
---

## Summary

The RJ9 connector (often referred to as RJ10 or RJ22) is a4-position, 4-conductor (4P4C) modular plug standard used to connect telephone handsets to phone bases.

| Pin Number | Standard Handset Color | Description                  |
| ---------- | ---------------------- | ---------------------------- |
| **Pin 1**  | Blue / White           | Handset Receiver (RX)        |
| **Pin 2**  | Yellow / Black         | Receiver / Microphone Ground |
| **Pin 3**  | Green / Red            | Microphone (TX) Ground       |
| **Pin 4**  | Red / Green            | Microphone Power / TX        |

#### Pinout Orientation

When looking at the gold pins of the male plug facing you (with the locking clip facing **down**), Pin 1 is on your **far left** and Pin 4 is on your **far right**. [[1](https://www.youtube.com/watch?v=miMuRXJVNYI&t=3)]

## Notes



## References

