carrier scanner

from The Free On-line Dictionary of Computing (8 July 2008)
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.

   (1997-03-16)