Difference between fxs_gs,fxs_ks,fxs_ls

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.[53] 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.[54] 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).

asteriskdocs.org/en/2nd_Edit … ECT-5.html

Thanks for your reply.