[1] It is an organization of people in a phone company which is responsible for programming the service and features purchased by residential and business customers into the central office.
Installing a telephone line is a complex process, involving coordinated work on outside plant and inside.
Inside plant work includes running a jumper on the main distribution frame and programming the switch.
Stored program control exchanges in the 1970s had teleprinter channels for entering and verifying translation information, which allowed centralizing these functions.
Generally, the existence of the RCMAC organization started with 1A switches from Bell Labs (later Lucent, now known as Alcatel-Lucent), from which the term "recent change memory" originated.