It's not really so easy to get some parts here in South America. "SOME"
suppliers think that our qtys. (say 100) which might be "high" volume
for some people here, are too low to even bother giving you a quote.
Plus, when you only want to make 1~5 equipments, and you need, lets say,
a transformer, you might end up paying 50U$S or more for five U$S 1
component....


Its not so easy here...

Mauricio Jancic
Janso Desarrollos
Microchip Consultant
(54) - 11 - 4542 - 3519

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Olin Lathrop
Sent: Mi=E9rcoles, 29 de Octubre de 2003 08:55
To: PICLIST@MITVMA.MIT.EDU
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

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