Can anybody suggest any efficient audio fed-back mechanism through telephone line
so 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)
But cannot hear any sounds at remote calling end. I have tried all frequencies in the range 300-650Hz by varying
POT 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.
[ I SAY SORRY TO ALL FORUM MEMBERS FOR POSTING THREADS ON THE SAME SUBJECT BASED ON TELEPHONE ]