Path: utzoo!dciem!nrcaer!scs!spl1!laidbak!att!pacbell!ames!mailrus!tut.cis.ohio-state.edu!bloom-beacon!XEROX.COM!Thompson.PA
From: Thompson.PA@XEROX.COM
Newsgroups: comp.dcom.telecom
Subject: Re: TELECOM Digest V8 #88
Message-ID: <880601-154524-5927@Xerox>
Date: 1 Jun 88 22:44:52 GMT
Article-I.D.: Xerox.880601-154524-5927
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Re:
----------------------------------------------------------------
>Subject: Three wire lines (was 2 line wiring)
>Date: 27 May 88 23:48:21 GMT
>Reply-To: mdf@tut.cis.osu-state.edu (Mark D. Freeman)

>My house was built in the 1920's and was wired for telephone with 3
>wires.  I can understand two or four, but three?  Why?

The three wire are TIP, RING and GROUND (or SLEEVE in the CO).  In a residence
phone with multi-party service it was used to split the ringing circuit.  For
two party service they would ring from either TIP or RING to GROUND.  The
conversation took place across TIP and RING.

	Geoff

Geoffrey O. Thompson
Xerox Corporation
475 Oakmead Parkway
Sunnyvale, CA 94086
		U.S.A
		
Telephone: (408) 737-4690
ARPA Mail: Thompson.OSBUNorth@Xerox.COM