If you remember playing adventure or dialing in to your favorite BBS at 300 baud, then perhaps you need this modem.
I bought it new in 1976. It powers up and shows appropriate lights for the mode it is set to. There are Originate, Answer, Full Duplex, Half-Duplex and Test settings. It does generate the appropriate tones when set to answer or test mode. I cannot test it with another modem to verify full functionality.