Trouvaille

Front:
VOR GROUND CHECK BEARING
VOR GROUND CHECK SYSTEM SWITCHING UNIT
TYPE DGI7614
SERIAL NO 0134
DG INSTRUMENTS LDT.
TRANSPORT-CANADA
(in a circle) 000 020 040 060 080 100 120 140 160 180 200 220 240 260 280 300 320 340 

Back:
MONITOR                INPUTS
   1     000 020 040 060 080 100 120 140 160
   2     180 200 220 240 260 280 300 320 340

Left: there is a parallel port (output) on the left side