On Mon, 19 Nov 2007 12:26:03 +1300
Jinx <joecolquitt@clear.net.nz> wrote:

> Looking around, I find a variety of phone line interfaces. Some are
> for simple ring detection, others are for analogue signals. I'd like to
> know if the circuit attached will do what I hope it will, and also
> what components (protection, isolation, steering etc) may need to
> be added


No, I don't think it'll work. The phone company detects the user by a DC
path. If you connect the transformer immediately, you'll effectively be
asking for a line. There should be a relay before the transformer (or a
DC blocking capacitor, but then you will still have to short that one out
on making the connection).

John
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist