James Blake <jblake@sirius.uvic.ca> (04/10/91)
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? james
"Paul S. Sawyer" <paul@unhtel.unh.edu> (04/11/91)
In article <telecom11.279.12@eecs.nwu.edu> jblake@sirius.uvic.ca (James Blake) writes: > 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? If your application is as simple as it sounds, the Bogen WMT-1 comes to my mind -- bridging transformer, with RCA jack <-> screw terminals. Paul S. Sawyer {uunet,attmail}!unhtel!paul paul@unhtel.unh.edu UNH CIS - - Telecommunications and Network Services VOX: +1 603 862 3262 Durham, New Hampshire 03824-3523 FAX: +1 603 862 2030
rlg@nosc.mil (04/11/91)
In article <telecom11.279.12@eecs.nwu.edu> you write: > 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? A quick-and-dirty hack to go from an audio jack to phone line: 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. These phones don't seem too particular about impedence. Messy, inelegant, may cause warts, etc. but it has worked for me. (Somebody will probably have something to say about this :) To go from the phone line to audio, consider a call-recording device. Randy Gregor | Computersmith rlg@xenon.sr.com or uunet!paralogics!compsm!rlg | POB 25-D +1 213 477 4338 | Los Angeles, CA 90025
Andy Jacobson <IZZYAS1@mvs.oac.ucla.edu> (04/12/91)
In TD V.11 #279 James Blake <jblake@sirius.uvic.ca> said: > 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? If you're willing to consider a 1/4 inch jack for your audio source, there is of course the Ma Bell "QKP" "QKT' or "QKTBT" voice coupler arrangement. These little jobs were provided usually in a type 30 jack housing, or occasionally engineered with a 1/4 jack in the side of a reworked 500 type phone set. Primarily for radio stations for the ubiquitous "phone patch" so often used for call in shows and remote broadcasts, in most arrangements they were bridged off of the co line and were turned on/off by a switch on the side of the associated phone. The old ones consisted of little more than a transformer for isolation, a capacitor (to prevent passage of DC?) and a zenor to limit the line level (and of course a 1/4 inch jack). They were crude devices, producing a characteristic distortion and giving a poor signal level match for broadcasting two-way conversations. Later versions contained more circuitry removing the distortion. Most stations that can afford them use expensive and well engineered bridges from non-telco vendors that clean up the audio and match the signal level. Many of these devices are made to work with 1A2 equipment, and are designed to be hooked up to the CO or KSU line, entirely replacing the phone set. I don't remember the names of any of the manufacturers, but they are available from any broadcast supply house such as Allied (Harris) Broadcast Supply. Andy Jacobson<izzyas1@oac.ucla.edu> or <izzyas1@UCLAMVS.bitnet>
John Higdon <john@zygot.ati.com> (04/13/91)
jartel!compsm!rlg@nosc.mil (Randy Gregor) writes: > In article <telecom11.279.12@eecs.nwu.edu> 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" <paul@unhtel.unh.edu> 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 !