Genuine US military AN/PRC-77 Portable Transceiver. Includes the important 14 pin screw on cap for the top right plug!! This seems to be the missing component to make these radios work from what I have seen. Includes original battery compartment box attached at the rear. Tested by putting 24V to the correct terminals on the back, plugging in a wire antenna and connecting the handset.
You can hear static on the handset, and the dials light up when switching its light on. Tuned it on 52.20 MHz and keyed up on a different radio and the PRC-77 picked up something from that.
Beyond this basic testing I do not know if this radio will do everything it is supposed to, as I do not have another one like it to test with. 920 channels across two bands using 50 kHz steps. 30.00 to 52.95 MHz (Low Channel); 53.00 to 75.95 MHz (High Channel). This includes the 6M ham radio band!