elisp: Terminal Type

 
 2.4.5 Terminal Type
 -------------------
 
 A “terminal” is a device capable of displaying one or more Emacs frames
 (SeeFrame Type).
 
    Terminals have no read syntax.  They print in hash notation giving
 the terminal’s ordinal number and its TTY device file name.
 
      (get-device-terminal nil)
           ⇒ #<terminal 1 on /dev/tty>