Air Force Specialty Codes (AFSC's) are used to denote what responsibility or job someone is performing in the Air Force. The system was overhauled in 1993 to better match recent restructuring and modern positions. The previous system of AFSC's began in 1954 after the Air Force modified the Army's MOS system that it had been using since it separated from the Army.
I have my some of my grandfather's military records which use the 1954 - 1993 system. All AFSC's on his records have 4 digit numbers
1411 and are sometimes followed by a letter
1235B. The new system for officers has numbers in the first two places, a letter in the third position, and a number in the fourth
Any explanatory listing of AFSC's that I have been able to find uses the new system. Where can I find an explanation of the old system?