| CD (carrier detect)
When two modems decide that they can
talk to each other, they generate a signal on the serial RS-232 interface
called carrier detect. CD remains present as long as the two modems are
connected, though it can be interrupted by a call-waiting signal if one of
the phone lines receives a second call. Sometimes this interruption is
enough to drop the data connection and let the phone ring. Some regard
this as a bug, others as a nice feature. It depends on the importance of
the incoming call. |