Path: utzoo!attcan!uunet!husc6!rutgers!bellcore!tness7!ninja!doug
From: doug@ninja.UUCP (Doug Davis)
Newsgroups: sci.electronics
Subject: Re: Modular Telephone Connector
Summary: modualer tele connectors, outer two wires
Message-ID: <14054@ninja.UUCP>
Date: 17 Sep 88 17:52:30 GMT
References: <4063@enterprise.UUCP> <1988Sep16.171228.16442@utzoo.uucp>
Reply-To: doug@ninja.UUCP (Doug Davis)
Organization: Lawnet, borrowing an account from db Systems, Fort Worth, Texas
Lines: 33

>The middle two are tip and ring.  It is not particularly useful to ask
>"which is which?", because the usual modular wiring components reverse
>them quite casually.  Modern phones are designed to be insensitive to
>the polarity.
>
>The outer two wires are not normally connected in residential wiring.
>They get used for various purposes in commercial phone systems and
>other specialized applications.
Actually some stuff (older phones and phone stuff) will be sensitive
to polarity. If i remember correctly, (some one will undoubtably correct
me if I am wrong) in a "properly installed system, the green wire is
tip, the red wire is ring.  On residental phone installations, if you
have two lines,  you can have RJ14C jacks installed. This gives you both
lines on the same modular connectors.  In this case the black wire is
supposably tip, likewise the yellow wire is ring. Be careful though,
some really ancient residental systems have +5 to +7 vac flowing though
the yellow/black pair.  This was to supply lights for the dials on older
telephones.


 "Never worked for the fone company, just used to hack on fone stuff a
   bunch a few years back.  Now, where did i put that 600ohm/600ohm
   transformer?"


---
doug davis                                        \ | /
Lawnet             -------------------------------- * -
                                                  / | \
{ killer, convex, motown, tness7, sys1}!ninja!doug
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