Editing Registered jack (section)

==RJ61==
{{See also|8P8C|Ethernet over twisted pair}}

{| class="wikitable floatright"
|+ RJ61 wiring (USOC)
! Pin !! Pair !! Signal
! width=160 | Color
|-
| 1 || 4 || Tip
| [[File:Wire white brown stripe.svg|37px]] White/brown
|-
| 2 || 3 || Tip
| [[File:Wire white green stripe.svg|37px]] White/green
|-
| 3 || 2 || Tip
| [[File:Wire white orange stripe.svg|37px]] White/orange
|-
| 4 || 1 || Ring
| [[File:Wire blue white stripe.svg|37px]] Blue/white
|-
| 5 || 1 || Tip
| [[File:Wire white blue stripe.svg|37px]] White/blue
|-
| 6 || 2 || Ring
| [[File:Wire orange white stripe.svg|37px]] Orange/white
|-
| 7 || 3 || Ring
| [[File:Wire green white stripe.svg|37px]] Green/white
|-
| 8 || 4 || Ring
| [[File:Wire brown white stripe.svg|37px]] Brown/white
|}

RJ61 is a [[electrical connector|physical interface]] that was often used for terminating [[twisted pair]] cables. It uses an eight-position, eight-conductor (8P8C) [[modular connector]].

This wiring pattern is for multi-line analog 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. [[Digital Signal 1|T1 line]]s use another wiring for the same connector, designated ''RJ48''. [[Ethernet over twisted pair]] ([[10BASE-T]], [[100BASE-TX]] and [[1000BASE-T]]) also uses different wiring for the same connector, either [[T568A]] or [[T568B]]. RJ48, T568A, and T568B are all designed to keep both wires of each pair close together.

The flat eight-conductor silver-satin cable conventionally used with four-line analog telephones and RJ61 jacks is also unsuitable for use with high-speed data. Twisted pair cabling is required for data applications. Twisted-pair patch cable typically used with common Ethernet and other data network standards is not compatible with RJ61, because RJ61 pairs 3 and 4 would each be split across two different twisted pairs in the patch cable, causing excessive cross-talk between voice lines 3 and 4, with conversations on each line literally being audible on the other.

With the advent of structured wiring systems and TIA/EIA-568 (now ANSI/TIA-568) conventions, the RJ61 wiring pattern 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.