A question about non-window terminals

[xinxiang]

Hi everyone,

I have a question about the lisp language in emacs.
I want to set the default face color and fontset by myself, but I still
want to use the default configure while using non-windows terminals.
Is there any function or env I can use to recognize the terminal type?
Like to check if the current emacs session is started with "emacs -nw",
use the default setting, otherwise use custom setting.

Does anyone konw the answer?
Thanks very much for your time!

Xin