TELECOM Digest OnLine - Sorted: Re: Wiring Two Lines on One Jack

Re: Wiring Two Lines on One Jack

Tony P. (
Sat, 12 Mar 2005 15:58:25 -0500

In article <>, says...

> In a message dated Fri, 11 Mar 2005 21:34:59 -0500, Marcus Didius Falco
> <> writes:

>> Many years ago the standard was somewhat different, and the yellow
>> wire was sometimes used as a ground. Then, for a time, I think the
>> yellow wire was used to power the lights on princess phones. Almost
>> certainly the yellow wire is either dead or shorted to one of the
>> other wires. Check this with a volt meter.

> The yellow wire was indeed used for ground, required for the generally
> used type of party-line ringing, and also for calling party
> identification when DDD came along.

> Two wires were required, as for all electrical circuits, for the
> lights on Princess and Trimline phones. They were normally on
> yellow-black. Usually a wall war was used, but there were also
> separate plug-in transformers with binding post terminals that could
> be put in an inconspicuous location and multipled (normally on the
> yellow-black) to several Princess or Trimline phones.

Yep -- I remember that setup well. There were different wall warts
depending on the configuration being set up. Our house had one but the
current was higher because there were two Trimlines and one Princess
in use.

> Later examples of Trimline phones got the power for the lights from
> the phone pairs (another task for the C.O. battery).

Yep, got one of those on my desk right now. A yellow Trimline to be
specific. Has green LED's to provide the lighting.

[TELECOM Digest Editor's Note: One thing I have noticed which is
different between the older Trimline phones (with a separate power
supply) and the newer units is that the newer units (with an LED to
light the buttons) run from telco battery instead of an external power
supply. The old units would stay lighted all the time unless you
flipped the switch to turn off the light bulb. The newer units (with
an LED powered from telco battery) are dark when the phone is on hook
and also go dark for a few seconds as the buttons are pressed. That
is unfortunate, because the older units also made very nice 'night
lights' in a darkened room. With the newer (telco battery powered
LED) units, you can not see the phone in a dark room until you have
already found it and have it off hook. PAT]

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