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Telephone & Data Wiring Installation for RJ11 and RJ4

RJ-11 (Telephone) Plug

Figure 1 is the wiring scheme for the plug side of an RJ-11 connector. The diagram is shown with the "hook clip" on the underside. The typical RJ-11 connector has six terminals. Usually, only the middle four pins are used. The POTS (Plain Old Telephone Service) residential telephone wiring generally contains two pairs of wires - designed for two separate telephone lines. The center pins (Red and Green) contain the first telephone line. Please note that business (digital) phone systems may be wired differently.

RJ-45 (DATA) Plug Wiring



The wiring scheme for the plug side of an RJ-45 connector in accordance with T-568B standards. The T-568B standard is the most commonly used. The wiring diagram is shown with the "hook clip" on the underside. The wall jack may be wired in a different sequence because the wires may be crossed inside the jack. The jack should have a wiring diagram or designated pin numbers/colors to match up to the color code below. When wiring a jack or an RJ-45 plug, remember to keep the “twist” as close as possible to the (jack or plug) receptacle. This will insure compliance with Ethernet wiring standards.

Specification T-568B

Pin # Color Pair # Name
1 white/ orange 2 Transmit Data +
2 orange 2 Transmit Data -
3 white/ green 3 Receive Data +
4 blue 1 not used
5 white/ blue 1 not used
6 green 3 Receive Data -
7 white/ brown 4 not used
8 brown 4 not used

(Even pin numbers are always solid color. Odd pin numbers are white/ stripe color.)

For reference purposes only, Figure 3 details the wiring scheme according to T-568A standards. Be sure adhere to EITHER the T-568B or the T-568A standard. Do not mix different wiring specifications within the same wiring installation.

Specification T-568A

Pin # Color Pair # Name
1 white/ green 3 Receive Data +
2 green 3 Receive Data -
3 white/ orange 2 Transmit Data +
4 blue 1 not used
5 white/ blue 1 not used
6 orange 2 Transmit Data -
7 white/ brown 4 not used
8 brown 4 not used

Crossover Cable
Some applications may require a crossover cable. The most common use of a crossover cable occurs in wiring together two Hubs. A crossover cable “crosses over” Transmit and Receive Data. Pins 1 and 3 are crossed over, and Pins 2 and 6 are crossed over. To build a CROSSOVER cable, simply wire one side according to specification T-568B, and wire the other side according to T-568A.


66 Block punchdown

66 block is a type of punchdown block used to connect sets of wires in a telephone system. They have been manufactured in three sizes, A, B and M.

A and B have six clips in each row while M has only 4. 

66 Block B series with 6 clips in each row. Jumper wires on the left connect the top pair with the bottom pair, allowing to split up to 10 devices




110 block is a type of punch block used to terminate runs of on-premises wiring in a structured cabling system. The designation 110 is also used to describe a type ofinsulation displacement contact (IDC) connector used to terminate twisted pair cables,[1] which uses a punch-down tool similar to the older 66 block.



Punchdowns are made with the pairs in order with the white-stripe wire first, then the colored wire.

Pair 1 white/blue - Blue
Pair 2 white/orange - Orange
Pair 3 white/green - Green
Pair 4 white/brown - Brown