vijay.k
New Member
hi friends,
When a telephone is made off hook, a dial tone is obtained in tel. line. 8)
If a key is pressed, DTMF tone of that digit is generated in the line (where the dial tone was already present).
Even in the presense of dial tone in the line, DTMF tone gets recognised properly by the exchange.(Then dial tone is stopped by the exchange).
So, the exchange sends the dial tone to the subscriber and at the same time also receives DTMF tone(of first digit) from the same subscriber through a single tel. line.....
how is it possible to detect DTMF tone(of first digit)in the presence of a dial tone in the line?
Or, what is happening internally in a tel. line while dialing the first digit?
Is it possible to stop the dial tone in the subscriber line without on hook?
Can any one, clear my doubt please?
vijay.k
When a telephone is made off hook, a dial tone is obtained in tel. line. 8)
If a key is pressed, DTMF tone of that digit is generated in the line (where the dial tone was already present).
Even in the presense of dial tone in the line, DTMF tone gets recognised properly by the exchange.(Then dial tone is stopped by the exchange).
So, the exchange sends the dial tone to the subscriber and at the same time also receives DTMF tone(of first digit) from the same subscriber through a single tel. line.....
how is it possible to detect DTMF tone(of first digit)in the presence of a dial tone in the line?
Or, what is happening internally in a tel. line while dialing the first digit?
Is it possible to stop the dial tone in the subscriber line without on hook?
Can any one, clear my doubt please?
vijay.k