Path: utzoo!telecom-request Date: Sat, 13 Apr 91 00:10 PDT From: John Higdon Newsgroups: comp.dcom.telecom Subject: Re: Phone Audio to RCA Jack Reply-To: John Higdon Message-ID: Organization: Green Hills and Cows Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 291, Message 9 of 10 Lines: 47 jartel!compsm!rlg@nosc.mil (Randy Gregor) writes: > In article is written: > > Has anyone ever come across a device which would allow one to take the > > line level out from an RCA jack to a telephone line and to take the > > audio from a phone to a RCA jack? > Get an old phone with a _carbon_ mic (the pop-out kind). Remove the > mic. Connect the audio to the mic contacts, and adjust the output > level. and "Paul S. Sawyer" writes: > If your application is as simple as it sounds, the Bogen WMT-1 comes > to my mind -- bridging transformer, with RCA jack <-> screw terminals. That bridging transformer is most important. Never, but never connect any unbalanced audio equipment directly to any telephone or other device directly connected to the network unless you are positive that isolation is provided within. One of the first commandments that we telco experimenters learned was "thou shalt not unbalance or introduce foreign battery on a telco line". If you connect unbalanced audio equipment without a transformer for isolation you will at best probably introduce hum and noise on the line and at worst introduce a safety hazard with unanticipated leakage currents. While the connection of a battery operated device MAY work OK without isolation, it is better to just obey the rule of making sure that your connection is isolated and balanced. If you leave such a device connected during the automated testing (done usually at night), a trouble ticket will be generated and you may have to deal with a repair man showing up. In the old days, this would have been tantamount to a visit by the FBI in our minds, but even though times have changed you do not need the hassle. Whatever you do, do not indiscriminately connect stuff to the handset transmitter contacts. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.ati.com | San Jose, CA 95150 | M o o !