ECN Forum Forums General Topics of the Trade Voice - Data - Video Discussion CAT 5/RJ31X phone Jack

I need to make up a drawing based on a project spec for a fire alarm system. The specs call for the use of two CAT5 cables that will run from the phone board to the alarm panel. Each line will be connected to a RJ31X jack for the alarm dialer. This tells me the line in form the phone comany and the in house phone line will be in the same cable. I presume that there is a color standard for the CAT5 cable used in conjunction with the jack. Is there a particular color order for the incoming and in house phone line tip/ring?

This is what I have found

and I would use the USOC standard where the pairs radiate out from 4 and 5 (4&5, 3&6, 2&7, 1&8) Bl, Or, Gr, Br)

That puts the phone in and phone out on separate twisted pairs.

Thanx Greg, is there a standard for the wire colors?

The USOC standard is
4&5 Blue B/W (Yes this one is different)
3&6 O/W Orange
2&7 G/W Green
1&8 B/W Brown

This is an old ATT standard I believe.

That is the current standard for an RJ61X jack, which is not the case here. Still, there's no reason that it cannot be used. It makes no sense to wire anything to positions 2,3,6 and 7 since they don't do anything in an RJ31X.

In the case of an RJ31X, there is not a defined color standard. The phone line just goes in on one pair and comes out on another. I use the white/blue pair for the line in and the white/orange for the line back out.