How to `start-process' in different terminal?

[Thorsten Jolitz <tjolitz@gmail.com>]

Hi List, 

when running Emacs on the console (without X) I use 'fbgs' to display
pdf files (converted to .tiff actally). This does not work with a
terminal multiplexer like tmux (running on e.g. tty), I have to switch
manually to e.g. tty1 to make it work.

Quite a lot of Emacs libs use start-process to display generated pdfs
with an OS dependent executable, for example "evince", always assuming 

,----[ C-h f display-graphic-p RET ]
| display-graphic-p is a compiled Lisp function in `frame.el'.
| 
| (display-graphic-p &optional DISPLAY)
| 
| Return non-nil if DISPLAY is a graphic display.
`----

is non-nil. I would like to fallback to "fbgs" if it is nil on
GNU/Linux, normally from an Emacs running inside a tmux session e.g. on
tty.  

How can I `start-process' in a different terminal (e.g. tty1) and switch
to that terminal in an Emacs Lisp program?

When I call `(terminal-list)' from Emacs instances on two different tty's I get
the same result:

,----
| (#<terminal 1 on /dev/tty>)
`----

and I don't find a function for switching terminal or calling cmd on
another terminal. 

-- 
cheers,
Thorsten