Connecting an RJ-11 cord to a RJ-45 jack FREE cabling and networking Helpdesk
 Question by Tre Jon posted 03 Aug 2004
 Connecting an RJ-11 cord to a RJ-45 jack
Hello, I am a manager at a daycare that has a RJ-45 jack for its phone lines. I would like to have a portable phone, but all of the portable phones I have seen are for RJ-11 jacks. Could I make a regular RJ-11 wire with a RJ-45 cap at the end so that I could plug into into the RJ-45 jack? If so, where do I place the four wires on the RJ-45 8 pins? Thanks
 Answer by Joseph Golan posted 03 Aug 2004
Dear Tre,

If your structured cabling system is recently installed, many manufacturers have increased the durability of their 8 pin moudular jacks to accept a 6 pin plug (RJ-11 type) without damage.

If the system is older, there may end up being damage to the outmost pins (1 & 8) if an RJ-11 style plug is inserted to an 8 pin jack.

Anyway to answer your question we really need to know if the jacks are wired to the T568A or T568B wiring standard. The difference between these is that pairs 2 & 3 are swapped. see the "references) link above for "Pinouts".

There is also a third possibilty that they are wired to the RJ-61X standard.

For RJ-11 (1 pair), RJ-14 (2 pair, RJ-25 (3 pair) and RJ 61X (4 pair) type wiring, please look at this link:

The trick here is to pickup the same pairs and conductors. For the RJ types called out above, the conductors of a pair are IDed as T (Tip) and R (Ring). In the T568A&B wiring diagrams the Tip side is the White conductor half of the pair and the Ring side is Blue, Orange, Green or Brown Conductor.

As an example for an RJ-14 to the three other wiring types:

Pair 1 Tip is White or Blue (Pin 4 of the RJ-14)
Pair 1 Ring is Blue (Pin 3 of the RJ-14)
Pair 2 Tip is White of Orange (Pin 2 of RJ-14)
Pair 2 Ring is Orange (Pin 5 of RJ-14)

For the T568A, T568B & RJ-61X:
Pair 1 White (Tip 1) to Pin 5
Pair 1 Blue (Ring 1) to Pin 4

T568A & RJ-61X only
Pair 2 White (Tip 2) to Pin 3
Pair 2 Orange (Ring 2) to Pin 6

T568B only
Pair 2 White (Tip 2) to Pin 1
Pair 2 Orange (Ring 2) to Pine 2

Hope this helps you.

Joseph Golan, RCDD

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