I have an Associated Press teletype which I believe is a Model 15, and a Model 19 keyboard (bought separately).  I'm brand new to this stuff.  My first question is:  Assuming these 2 are working, can I just plug the keyboard into the main unit and it should work? Related to this: Where the Associated Press units a "cutdown" version with certain things missing because they weren't strictly needed for a receive-only setup?