Can any one tell me the difference between the three signalling trunks.I was very confused about these three.can u give some examples .please reply
Ground start (gs)
Kewlstart (ks) Loop start (ls)
The difference between loop start and ground start has to do with how the equipment requests a dial tone: a ground-start circuit signals the far end that it wants a dial tone by momentarily grounding one of the leads; a loop-start circuit uses a short to request a dial tone. Though not common for new installations, analog ground start lines still exist in many areas of the country. Ground start is really a rather strange thing, because it doesn’t exist in its analog form in Asterisk, so technically, there is no ground signal happening, but is rather a signaling bit that is intended for analog circuitry that historically would have been at the end of the T1. If this does not make much sense, don’t sweat it; chances are you won’t have to worry about ground-start signaling. All home lines (and analog telephones/modems/faxes) in North America use loop-start signaling. Kewlstart is in fact the same as loop start, except that it has greater intelligence and is thus better able to detect far-end disconnects. Kewlstart is the preferred signaling protocol for analog circuits in Asterisk.
To configure a signaling method other than kewlstart, replace the ks in fxsks with either ls or gs (for loop start or ground start, respectively).
Thanks for your reply.