The AN/PRC 77 entered service in 1968 during the Vietnam War as an upgrade to the earlier AN/PRC 25. It differs from its predecessor mainly in that its final power amplifier stage is made up of solid state components and does not use vacuum tubes. The AN/PRC-77 can use voice encryption devices which the AN/PRC-25 cannot. Today the AN/PRC-77 has largely been replaced by SINCGARS radios, but it is still capable of inter-operating with most VHF FM radios used by U.S. and allied ground forces. It is commonly nicknamed 'The Prick' by the U. S. Army and U. S. Marine Corps (Wikipedia).
For more information, check Wikipedia - PRC-77 och RA145/146.
Some of the sockets are UV-mapped! The native file is Sketchup.
Next to the radio is the black pluggs to the antenna holder and the audio sockets.