Carrier scanner
<security> (Or "wardialer") A program which uses a
modem to dial a series of phone numbers (say, from 770-0000 to 770-9999), and keeps a log of what phone numbers answer with a modem carrier.
The results of such a search were generally used by people looking to engage in
random mischief in
random machines.
Since the 1980s, wardialers have generally fallen into disuse, partly because of easily available "
caller ID" technology, partly because fax machines are now in wide use and would often be logged as a carrier by a wardialer, and partly because there are so many new and more interesting venues for computerised mischief these days.