lauren@VORTEX.UUCP (Lauren Weinstein) (03/09/86)
The question of whether or not a LD carrier properly detects answered calls is based on two factors: 1) The local network interface at the CALLED end of a given circuit 2) Arrangements to pass supervision info back to billing computers AT&T's network is designed to properly detect and pass back answering supervision for all calls. The other carriers vary widely, not only on a carrier by carrier basis but also in some cases on a call by call basis. Some carriers simply don't pass info back at all, and operate totally on a timed basis to "guess" about when a call is answered. Some other carriers pass the info back properly on SOME calls, depending on the sort of trunk interfacing (e.g. equal access) in place at the CALLED end of the circuit. In other words, if a carrier has equal access in place at the point you're CALLING, and if they have facilities to pass that info back to their billing computers, answering supervision will be available for that call. If you happen to be calling a point that is not interfaced in that manner, you may often find yourself billed based on a timing "guess" instead of answering supervision--so you may well get billed for a call that never answered in such a case. --Lauren--