The message "Stopped (tty input) comp" most frequently occurs when you
have done "comp &" rather than just "comp". The program "comp" expects
to be able to prompt you for more information, and it cannot do that
if you run in background.  That is why it returned the error "stopped
tty input".

When you get the message "Stopped (tty input) comp", type:

	fg

at the athena% prompt in the same window as that message.  That will
bring the comp program to foreground, and allow you to type "send"
there, as you would expect.