Article View: sci.electronics
Article #21176Conferencing two phone lines
From: Adam Levin CATS
Date: Tue, 18 Apr 1989 15:16
Date: Tue, 18 Apr 1989 15:16
31 lines
1644 bytes
1644 bytes
This topic was pretty well hashed out on the net about half
a year ago, but the exact method wasn't covered.
I have two phone lines that I want to be able to "conference"
from time to time. We learned that you shouldn't just connect
tip-to-tip and ring-to-ring because of voltage differences between
your location and the phone company (not to mention if a call
should come in on one line while a call is in progress on the other).
It was advised that one needed to use an isolation transformer
between the two lines. As I recall, this was a 600 Ohm 1:1
transformer. I bought such a beast at Radio Shack, but connecting it
to the phone lines seems to load them too much; there is an
obvious degradation of the signal. I made the connection like so:
Tip 1___ ___Tip 2
| |
\ \
/ /
\ \ 600 Ohm 1:1 transformer
/ /
Ring 1___| |___Ring 2
Has anyone successfully built a device like this?
I'd really appreciate hearing about it! Adam
--
Adam Keith Levin -- CATS Commodore-Amiga Technical Support
1200 Wilson Drive / West Chester, PA 19380 (215) 431-9180
BIX: aklevin UUCP: ...{amiga|rutgers|uunet}!cbmvax!adam
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<6612@cbmvax.UUCP>Path:
arc1-ca.pugleaf.net!utzoo!dptcdc!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!cbmvax!adamShow Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!dptcdc!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!cbmvax!adam From: adam@cbmvax.UUCP (Adam Levin CATS) Newsgroups: sci.electronics Subject: Conferencing two phone lines Message-ID: <6612@cbmvax.UUCP> Date: 18 Apr 89 15:16:14 GMT Reply-To: adam@cbmvax.UUCP (Adam Levin CATS) Distribution: usa Organization: Commodore Technology, West Chester, PA Lines: 31