Factual error: In this episode, the regulars receive and respond to letters from a Fourth-Grade class in Hawkeye's home town. Charles receives one from a little girl who says she's sent him a birch leaf. Unfortunately, the leaf he removes from her glassine envelope is a maple leaf. (Note: there was no indication that this was supposed to be her mistake.)
Factual error: After the opening credits it cuts to Klinger at Mail Call, and Father Mulcahy's reading Ring Magazine which is dated December 1969, 16 years after the Korean War ended.
Factual error: When BJ opens the first box of tongue depressors the tongue depressors are packaged in a plastic bag inside the cardboard box, my research says that plastic bags were not available in the early 1950's. (00:08:06)
Factual error: When Klinger's walking with Captain Allen and the Stars and Stripes photographer, just before their introductions to "Ben" they pass an empty corrugated box with its flap open, and the recycling symbol can be seen on the flap. Recycling symbols were not in use until about 20 years later.
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.