The AN/UGM-11 (Wavetek model 404) is a test pattern generator for RTTY equipment.

The units have shown up on eBay, etc. over the years but no one has turned up a manual.

I made a FOIA request to the Navy for the manual several years ago, but keep getting told "it is being reviewed".

It looks like this-

I did a little reverse-engineering several years ago but it was painful and incomplete

Cheers,