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From: hbo@sbphy.ucsb.edu (Howard B. Owen)
Newsgroups: comp.sys.amiga
Subject: Re: Extention cables
Message-ID: <1053@hub.ucsb.edu>
Date: 15 Dec 88 17:10:39 GMT
Sender: news@hub.ucsb.edu
Organization: UC, Santa Barbara. Physics Computer Services
Lines: 24

In article <2467@antique.UUCP>, cjp@antique.UUCP (Charles Poirier) writes...

>As I recall from some earlier discussion, (someone will correct me if
>I'm wrong), you have to be careful with phone extender cables.  Phones
>apparently don't mind having certain pairs of wires in a four-wire
>cable cross over from one end to the other.  Your keyboard, however,
>can be permanently fried by such a cable.  You should test the cable
>with a continuity check meter connected across the two ends of each
>wire -- use the connectors of your original cable for reference.  Use
>the extender cable only if it has only straight-through connections.

   The four wire phone cable I use has color coded conductors, and the RJ-11
connectors I use are made of transparent plastic. Rather than using a VOM to
check if the cable is wired straight-through or crossed, I just check the order
of the colors as viewed through the connector on each end of the cable. If the
order is the same with respect to the tab on the top of each connector, then
the cable is wired straight-through. Of course, testing a cable with a 
continuity checker will tell you if each conductor is working properly, but 
so in many cases will plugging in the cable!

--
Howard Owen, Computer Systems Manager           internet: hbo@sbphy.ucsb.edu
Physics Computer Services                       BITNET: HBO@SBITP.BITNET
University of California, Santa Barbara         HEPNET/SPAN:   SBPHY::HBO
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