Date: Fri, 16 Oct 92 03:34:12 -0400
From: shri%unreal@cs.umass.edu
Newsgroups: comp.dcom.telecom
Subject: Re: Old Telephone Wiring at Network Interface
Organization: UMass, Amherst, MA 01002 + Temporal Sys & Comp Net, Bombay, India
X-Submissions-To: telecom@eecs.nwu.edu
X-Administrivia-To: telecom-request@eecs.nwu.edu
X-Telecom-Digest: Volume 12, Issue 783, Message 4 of 10

In article <telecom12.772.8@eecs.nwu.edu> arnold@Synopsys.COM wrote:

> When I opened the old network interface I had trouble finding the
> yellow/black pair.  I eventually found the yellow wires connected to a
> screw connector.  There is also a wire running from this connector to
> the new network interface.

> The wire does *not* go to any of the connectors used for phones.  Is
> it some sort of ground?  Was it used for powering Princess phones?

The wire yellow and black got to A/A1 for (I think thats what its
called) Answer supervision, used on exclusion key phones. Thats
mumbo-jumbo for I'll short A to A1 when I pick up the call.

I had exactly the same network interface configuration in my apt when
my second line was installed as you describe. That is what led to the
EASA-phone problem I bugged people on this list with a week or so ago.
:-) So I can share some acquired wisdom.

The old network interface, inside your house, has an extra RJ11 in the
bottom to which the phone line comes, and this is jumpered to the main
RJ11 jack in the middle of the panel. If the main RJ11 seems bad, you
are supposed to be able to plug you phone directly to the bottom RJ11
and get it to work there for instant debugging -- "See its not
MaBell's problem there!" (I don't understand really what great end this
achieves :-) Maybe they thought then that the RJ11 female was the
major failure point ... !) Anyway ...

The NET tech who wired my phone for me wired my existing line into the
bottom RJ11 and the new line into the front-main RJ11.  So the
Red-Green goes to the bottom RJ11, the yellow-black go to the main RJ11.

Only, the yellow-black from the bottom RJ11 continued to be remain
where they were screwed in, ie right on the lugs that were now used
for the new lines tip-and ring, ie. the yellow-black from the new
network interface in the basement.

That's fact one ... ( I discovered the facts the hard way, in reverse! :-)

Now fact two ...

My answering machine on my old line seems to do that A/A1 short
whenever it picks up the phone. Now remember, by fact one, the old
lines yello-black for A/A1 was screwed with my new line tip/ring!.
Thus it would just short the tip and ring on my new line, whenever it
picked up the call on the old line.  For a long and very painful week
I was wondering why my EASAphone on the new line would go dead only
when the answering machine on the old line picked up an irrelavant
call!

Moral: when you wire the phone to the jack, disconnect everything,
isolate the yellow-black pair from each RJ11 and tape or clip them.

Then connect the red-green of each RJ11 to the red-green or
yellow-black of the telco line.

And to think my wiring was done by the NET techie, who made that
gaffe!!

Oh, BTW, do all answering machines do that A/A1 short? Specifically
does the Uniden model AB480B do it? (single micro cassette phone cum
ans machine, beeperless remote VOX/CPC, Toll saver, memo etc, in
recent COMB catalog ?) I could really use this feature for some neat
an-swearing messages!


shrikumar (shri@legato.cs.umass.edu, shri@iucaa.ernet.in)