An intercept message
is what you hear on the telephone
when a call
doesn't go through. Some examples of intercept messages:
"The number you have reached has been disconnected. Please hang up and try your call again."
"All circuits are busy now. Please try your call again later."
"If you'd like to make a call, please hang up and try again, if you need help, hang up, and then dial your operator."
Intercept messages give the caller some clue as to why the call didn't go through, instead of leaving them listening to a cryptic tone. Expecting the general populace to understand more telephone tones than "ring", "busy", and "receiver off hook" is probably giving them too much credit. }:)
Intercept messages are so named because in old telephone switches, the intercept was actually a contact in the switch that would "intercept" another contact as it moved into an invalid area.