vinodquilon Posted February 23, 2010 Report Share Posted February 23, 2010 Can anybody suggest any efficient audio fed-back mechanism through telephone lineso that the telephoning person can hear audio beeps, by which he can check the status of remotely controlled device (teleremote control).I have tried two circuits (see two attached files)http://www.scribd.com/doc/27346744http://www.scribd.com/doc/27346875But cannot hear any sounds at remote calling end. I have tried all frequencies in the range 300-650Hz by varyingPOT in the 555 astable audio beeps generator. But no result.I have selected this range as in this range there is no possibility for any DTMF tones.Thus audio frequency correctly fed-back to telephone line without detected by DTMF IC.Audio beep relay turns on only after off-hook relay get activated.I know that, in normal telephone line our vocal audio is captured by Mic, in turn converted into AF electrical signals. To check further fed-back mechanism ( & to imitate in my project),I opened my telephone set. But nothing can find out on a small, but complex circuit board inside the telephone set. Does Anyone knows any circuits (that should be of workable) ??? I forgot to say, I am feeding square pulses of audio frequency.fedback1.pdffedback211.pdf Quote Link to comment Share on other sites More sharing options...
vinodquilon Posted February 23, 2010 Author Report Share Posted February 23, 2010 I think all these problems can be solved by using RC or wein bridge oscillatorat audio frequency. Thus replacing square pulses with sine waves.10k will be replaced with 470 ohm at coupling path. What about my prediction ??? Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 23, 2010 Report Share Posted February 23, 2010 Please post your schematics here[/]b] instead of over at SCRIBD that takes all day to wake up.You have a value of 10k for R5 that creates high attenuation of your audio sound signal. Quote Link to comment Share on other sites More sharing options...
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