whalesong

whalesong n.  The peculiar clicking and whooshing sounds
   made by a PEP modem such as the Telebit Trailblazer as it tries to
   synchronize with another PEP modem for their special high-speed
   mode.  This sound isn't anything like the normal two-tone handshake
   between conventional modems and is instantly recognizable to anyone
   who has heard it more than once.  It sounds, in fact, very much
   like whale songs.  This noise is also called "the moose call" or
   "moose tones".