This is a Flesher Corp, TU-170 RTTY terminal unit.
It appears to have been modified, there is a toggle switch
mounted on the top marked 'TAPE XMIT ON/OFF'.

Otherwise it looks clean. I have not plugged it in.
It comes with a manual which includes a schematic.

If you were wanting to fire up that old TTY teletype
unit, here's what you need. If you will pay for
shipping or arrange a meeting at a convenient spot
then it is yours.

Contact me via email: chris at yipyap dot com

Chris