I bought this neat little piece of test equipment in an online Goodwill auction. Not much military surplus electronic equipment shows up there, but every now and then something cool pops up.
This test set appears to be for measuring distortion of data bits in teletype current loop signals, which would need to be corrected with mechanical adjustments of the device under test. I found some incomplete technical manual scans online, but unfortunately not including a schematic diagram, service information or operating instructions. I have a truncated scan of the first four pages of operator’s manual TM 11-6625-207-10, and a scan of maintenance manual TM 11-6625-207-20 which simply doesn’t include much useful information. I hope that I can find more detailed documentation so that I don’t need to reverse-engineer the thing to get it working.
The set is dirty, and needs a new line cord and two new toggle switches. I think it will clean up nicely, though.
Update 1: Robert Downs WA5CAB says that he will be able to provide reprints of all of the necessary manuals once he gets some things sorted out. Yay!
Update 2: Jack K2TTY says that this unit was also known as the Atlantic Research TDA-2.