RJ61
See also: 8P8C and Ethernet over twisted pairRJ61 is a physical interface often used for terminating twisted pair type cables. It is one of the Registered Jacks, and uses an eight position, eight conductor (8P8C) modular connector.
RJ61 specifies the wiring pinout of the connector as follows:
| Pin | Pair | Wire | Color |
|---|---|---|---|
| 1 | 4 | tip | White/Brown |
| 2 | 3 | tip | White/Green |
| 3 | 2 | tip | White/Orange |
| 4 | 1 | ring | Blue/White |
| 5 | 1 | tip | White/Blue |
| 6 | 2 | ring | Orange/White |
| 7 | 3 | ring | Green/White |
| 8 | 4 | ring | Brown/White |
This pinout is for multi-line telephone use only; RJ61 is unsuitable for use with high-speed data, because the pins for pairs 3 and 4 are too widely spaced for high signaling frequencies. T1 lines use another wiring for the same connector, designated RJ48. Ethernet over twisted pair (10BASE-T, 100BASE-TX and 1000BASE-T) also use a different wiring for the same connector, either T568A or T568B. RJ48, T568A, and T568B are all designed to keep pins close together for pairs 3 and 4.
The flat 8-conductor "silver satin" cable traditionally used with 4-line analog telephones and RJ61 jacks is also unsuitable for use with high-speed data. Twisted pair cabling must be used with RJ48, T568A and T568B. Note that data twisted pair patch cable used with the three data standards above is not a direct replacement for RJ61 cable, because RJ61 pairs 3 and 4 would be split among different patch cable twisted pairs, causing cross-talk between voice lines 3 and 4 that might be noticeable for long patch cables.
With the advent of structured wiring systems and TIA/EIA-568-B conventions, the RJ61 pinout is falling into disuse. The T568A and T568B standards are used in place of RJ61 so that a single wiring standard in a facility can be used for both voice and data.
Read more about this topic: Registered Jack