Zieres.wbst@XEROX.COM (Gary) (11/18/86)
Can anyone give me a circuit for connecting a phone line to broadcast over a stereo system? I only want to use the stereo to amplify and play over the stereo in a "one way" mode. I know radio shack has a device for recording into a tape player (costing over $20, which probably consists of a 50 cent isolation transformer), but I would like to build one cheaper. I think that simply an isolation transformer would work, but I don't know the ratio (or input impedance). Any of you telephone jocks out there that could give me a suggestion? - Gary
pozar@well.UUCP (Tim Pozar) (11/27/86)
>Can anyone give me a circuit for connecting a phone line to broadcast >over a stereo system? The circiut can be made very easliy out of two .1uf disk caps, and a 10k to 600 ohm tranformer. WARNING! This circuit is not FCC accepted. Ahem, now that I said that... Just hook it up to the red and green wires on the block. The caps are to block DC to the transformer and prevent the Telco equipment from seeing a "off-hook" status. In order to keep the line up, you should put a 1k resistor across the red and green wires. You could even put a switch in series to act like a switch hook. .1uf Green __| |____ _________\ To consumer level/impeadence | | )||( / audio source Telco 600 )||( 10K .1uf )||( Red __| |____)||(_________\ | | | / ----- --- -
ihm@ucbvax.Berkeley.EDU@minnie.UUCP (12/01/86)
I believe you can bridge a telephone line into the aux input with reasonable results by connecting T & R to the two leads of the aux input each through a 10 mf capacitor. Beware though of the sharp surges in the input from such things as dial pulses or line hangup/pickup. Cheerz-- <>IHM<>