Hello,
I finally got my circuit working... well almost. I use a pic chip with picbasic pro, I output DTMF and this goes through a filter shown in picbasic manual:
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From my scope I can see some 40v spike at the pin output and after the filter I do not see much maybe a few volts. This goes directly to an audio transformer. Is it normal to have 40v spike (the signal looks pretty nice). WHen I put a modem speaker at the pin output I can hear the dialing and maybe a third in strenght (sound) after the filter. At the output of the transformer I have an AC 250v capacitor. The pichip dials my phone, and I receive maybe 50% of the calls. Should I be using the filter? (I am not using an amplifier as mentionned in the manual) Is the 40v good to put directly on the transformer? Also from the speaker I hear a lot of background noisethanks k