Hello Ericgibbs and Audioguru,
Ericgibbs;
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Are you wanting to use the remote phone keypad to generate the DTMF tones?
[you can/could purchase small handheld tone generators]
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Yes, I'm using remote keypad.
I will really need MT8870D IC, as per what I read, it seems that I can attached the MT8870D(tone receiver) to the tips and rings as I don't need a tone generator.
I looked MT8870D datasheet and it seems that I can connect the tips and rings of the input, I guess that this is pin: IN + and IN - of this MT8870D datasheet(page 7 figure 6 ), Am I correct ? , see below;
**broken link removed**
Should I use figure 6 (page 7, Differential input configuration) or figure 9 (page 9 single ended input configuration ) ? Can you tell me briefly what the difference are btwn these to setup ?
Do you remember, you provided me a shematic few days ago : (3 rings to 1 pulse output) is this builted according to 90AC volts? If this is the case, I guess I can take the left part of this cct and connect it to MT8870D for protection purpose ?
What do you suggest ?
Hello Audioguru,
I would like to avoid power supply, as per what I read, If I answer the call, the Voltage will drop to 5 to 15 DC, than if I take this power to supply my MT8870D, I won't need any other power source. I guess you are providing me this info for testing purposes ?
Brgds/Charlie123