MT8870 Question

I have a DTMF tester diagram using MT8870 the circuit connected to the telephone line. When I press any key in the telephone it will output the converted binary value & displaying through the output LED’s.

My question is

For example let say my land line number is 1234 & my friends land line number is 5678.

When HE DIALED my number from his land line phone what is displaying in the DTMF tester circuit?
Is it displaying the converted BINARY value of his number (5678) or my number (1234)?

Thanks

During dialling nothing should be displayed, the dialling tones only go to the exchange, not to the receiving phone. Once you've answered the phone, any numbers your friend presses should be displayed by your DTMF circuit - but your number, and your friends number, are nothing to do with it.

If you're looking for caller-ID, then that's a completely different thing!.

Thanks Nigel.

Oh I see the dialing tone goes to the phone EXCHANGE not to the phone. I thought other way.

When I lift the phone can I see his number in binary form?

Or does he need to press some numbers while calling me.
It means when he is calling he is pressing number “1” so I can see that in my circuit that he has pressed number “1” through the LED’s.


I asked this because this M8870 have 5 output LED’S.I want to detect my friends number.

Suraj143 said:

Thanks Nigel.

Oh I see the dialing tone goes to the phone EXCHANGE not to the phone. I thought other way.

When I lift the phone can I see his number in binary form?

Or does he need to press some numbers while calling me.
It means when he is calling he is pressing number “1” so I can see that in my circuit that he has pressed number “1” through the LED’s.


I asked this because this M8870 have 5 output LED’S.I want to detect my friends number.

Click to expand...

You can't detect your friends number without caller-ID, and the M8870 outputs a 4 bit code signifying the number pressd (from 0 to 15).

Oh I see then I have no chance to detect my friends number.

Then of course I have to control some home appliances trough this M8870 circuit diagram.

Example press 1 = open relay one
Press 2 = open relay two etc…

Can you tell me what I can do with my M8870 circuit?

Suraj143 said:

Oh I see then I have no chance to detect my friends number.

Then of course I have to control some home appliances trough this M8870 circuit diagram.

Example press 1 = open relay one
Press 2 = open relay two etc…

Can you tell me what I can do with my M8870 circuit?

Click to expand...

Like you said, use it to control things over the phone, there have been numerous projects like that over the years.