It is likely that the disconnect signal from the exchange will be CPC. This is more common than line reversal. It is simply a momentary break in the loop current - i.e. 0V for maybe 500 ms. The following link provides some good info on this:
http://www.sandman.com/cpcbull.htmlThere are also some useful comments in this link, especially at the end Neill's comments about timing of CPC signals:
http://www.voip-info.org/wiki/view/Asterisk+Disconnect+SupervisionIt looks like the Digium card should detect CPC provided you are using the Kewlstart and not just Loopstart:
http://kb.digium.com/entry/30/My experience in the UK is that the Telco does not always deliver a CPC signal. Sometimes you have to call them and ask for it to be enabled on a line. Neill's comments suggest that they may also be able to adjust the length of time used for the CPC signal and that a longer time is likely to work better than a short time with Asterisk. Of course, Kuwait may not be the same although the influence of UK standards can often be seen in the telephone systems in other non-US countries.
If you are getting a CPC signal and the Digium card is not detecting it then you may find that adjusting flash and debounce times in chan_dahdi will help. This is because you need the card to be able to distinguish between a flash hook and a CPC signal. You also don't want it to ignore the CPC signal just because it is shorter than the debounce setting. Hope this helps.
