% cd /bin
  % ls -l
  total 3464
  -rwxr-xr-x  2 root 32768 Oct 19  1996 STTY
  -rwxr-xr-x  2 root  5120 Oct 19  1996 <Ctrl/]>  (characters not
  echoed)

  TELNET> SEND AO
  ^O
  %

      During a directory listing, the TELNET escape sequence (not
      echoed to the screen) returns to TELNET prompt. The SEND AO
      command aborts the UNIX ls command.