[Asterisk-Users] RE: Caller ID

[Paul Crick]

> The reversal detection is a complete waste of time. Totally
> unnecessary. Pointless. A line break detector would have much
> more use, as it would give a reliable disconnect detection on
> many lines.
Hmm.. but wouldn't reversal detection help those people who are in the UK
and want to receive caller ID?

I guess you could watch out for the CPE alert tone that's issued after the
line reversal, but I have some vague recollection that maybe you need to
provide a load so that wetting current can flow or something after the
reversal. SIN 242 rings a bell - it's a BT technical document that describes
the protocol exactly. All the SINs are available at www.sinet.bt.com

Hmm.. reading up, you could probably get away with just monitoring for the
alert tone then? I bow to the greater knowledge of the true techies on the
list.. I guess European caller ID is one of those big problems, with lots of
countries using lots of different protocols - I think some scandinavian
countries even use on-hook DTMF..

Easy answer: Get a digital circuit! :-)