Also look at http://www4.tpg.com.au/users/talking/TaxiPhonePage1.html I have had this work very well. HTH z ----- Original Message ----- From: "Olin Lathrop" To: Sent: 29 October 2003 11:55 Subject: Re: [PIC:] PIC DTMF > Bob Ammerman wrote: > > You could consider capacitive coupling. > > That would work in theory, but then you still have to deal with the large > common mode noise that can be considerably larger than the signal. A > transformer takes care of this nicely. > > I also don't understand why these transformers are so hard to get. They > are common and available here in North America. At the very least, surely > one of the suppliers up here will ship to South America (or wherever the > OP was). > > > ***************************************************************** > Embed Inc, embedded system specialists in Littleton Massachusetts > (978) 742-9014, http://www.embedinc.com > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads