Trivia: There were no American planes shot down over the Sea of Japan during the Korean conflict. It is rumoured that producer/director Larry Gelbart knew that, but wrote Henry Blake's death scene as he was very unhappy with the way Mclean Stevenson had left the show, and was determined to make it clear that there was no way he would be coming back.
Trivia: The Consultant whom Hawkeye and Trapper meet in Japan is played by Alan Alda's father Robert.
Trivia: When Frank demands the Greek soldier's name and serial number, he gives Frank the number in Greek numerals. It translates to 2688125. (00:10:15)
Answer: It is actually Cencompac for Central Command of the Pacific. It is like the headquarters for all military activity in the Pacific Region (Japan, Korea, Okinawa, etc. The newer version of that is United States Pacific Command (USPACOM).
EMTurbo
And the abbreviations were used mainly by the Navy. Especially CENCOMPAC.
Https://en.wikipedia.org/wiki/United_States_Indo-Pacific_Command.