One of my customer has 12 regular co lines,now they changed their service provider keeping the same no. of lines.This seemed prety easy but when i connected the new lines to the sx-200 El system, all trunks constantly rings bac on the console & if i try to access any trunk via att. access it shows locked. But still they are recieving incoming calls. The trunks are programmed on ls/gs trunk cards & the system uses LW 17.