Lot of 2 Hubbell/Pulsecom LIU-403 line interface units w/instructions

Lot of two Hubbell / Pulsecom model LIU-403 line interface units with instructions and boxes. These are marked "D105469-1" and have bar code stickers with "D4L1R5B4AC". According to the instruction sheets these are "ANSI T1.403-1989 compatible". The instructions are dated 1992.

These are from the estate of an industrial telecommunications engineer and ham radio enthusiast. We don't know much about them, but we don't think that they've ever been used as they have some sort of protective plastic covers over the connections on the ends of the boards. We have not tested these and the boxes have wear and soil from storage.