The base code '/20WC35A' specifies the connector's shell style, finish, size, insert arrangement, and contact type. '/20' denotes a wall mount receptacle. 'W' indicates an Olive Drab Cadmium over Electroless Nickel finish. 'C' signifies shell size 13. '35' refers to a MIL-STD-1560 insert arrangement, which, combined with the shell size, determines the contact count and size. 'A' specifies a pin insert, less contacts. The suffix 'N' indicates a normal keying position, which is used to prevent cross-mating. The D38999 prefix indicates full compliance with the official United States Department of Defense interconnect framework for circular connectors.