Lot 3 Pulsecom model 4T0-3L1 4-wire transmission only channel units

Lot of three Hubbell / Pulsecom transmission only channel units, model 4T0-3L1 These modules are marked "D105095-1" and also have bar code stickers marked "D4C0P775AA". Two of these have the original instructions. According to the instruction sheets, these are "4-wire, 600 ohm transmission only channel units". The instructions are dated 1990.

These are from the estate of an industrial telecommunications engineer and ham radio enthusiast. We don't know much about them. We have not tested them and the boxes are worn and dirty from storage.