dtmf dialer question

electromanj

Hello. This weekend i built a phone dialer with the bs2. I made the daa that was in the schematic. I hooked it up to the phone line and could clearly hear the touch tones on another phone. The phone I was calling never rang. I also programmed in to dial 1 and the area code and it stop dialing after the first four digits and the operator answered! Any ideas?

Chris Savage

Hello,
·
·· Are you using a BS2 or another model of BASIC Stamp?

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Chris Savage
Parallax Tech Support

electromanj

I am using the basic stamp 2 homework board.

Chris Savage

The H/W Board has 220 Ohm resistors in line with each I/O pin.· These may be attenuating your signal some.· You may need to boost the signal going to the line for it to be detected.

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Chris Savage
Parallax Tech Support

electromanj

Should· I use the stamp to drive an amplifier?

FlyingFishFinger

Hello-
Youu could try replacing the 1K resistor on the Stamp side of the circuit with something along the lines of 800ohms to compensate for the 220ohm resistors on the pin already.

I am attempting to do something similar (and a bit more extensive). Did you use the exact parts labeled in the diagram (I'm assuming we're all referring to NV #19, correct?)? Because when I checked the part numbers, at least the Sidactor turned up a part with a different voltage rating. Remeber, the article is 10 years old (phew...when I think about that, that's a really long time)...the part numbers may have changed.

And, I was wondering if someone could point me to some simple ring-detector circuits so I can recieve incoming calls to the Stamp...

Thanks

Rafael

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You've got to play the game.
You can't win.
You can't break even, except on a very cold day.
It doesn't get that cold.
~Laws of Thermodynamics~

electromanj

Interesting, will try and post results.