Can I read someone else's environment?

[Bill Silvert]

I just kludged together a message system that puts a short note on the
alert line (#25) of someone else's terminal.  This is preferable to
write(1) for us, since we are usually editing files when a message
scrambles the screen.  For hard-wired terminals I can get the terminal
type from /etc/ttytypes, but is there any way I can read the terminal
type for a dial-up line so that I know what escape codes to send?