I picked up a Model 26 Teletype which cane with a Western Union Simplex Printer Wiring Cabinet 2-B.  The box has two blocks of three 1/4-inch jacks (labeled "Cordless Table Jack Unit 2-B). On top of these is a large 5-inch diameter socket which accepts either a 17-B Polar Relay or a Combination Wheatstone Relay 1G. The socket is labeled "WU Tel Co. Radio Interference eliminator 9-A".

I cannot find any references to this wiring cabinet on the internet at all, but I can find images of the relays and the Cordless Table Jack boxes.

Does anyone know what this is or have any documentation?