Recent Change Memory Administration Center

RCMAC stands for Recent Change Memory Administration Center, sometimes mistakenly called Recent Change Message Accounting Center, in late 20th century Bell System parlance. Its purpose is to use centralization, automation, and specialized labor to cut the cost of installing switched service customers and changing their service features.

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. Middle 20th century Crossbar switches had no computer, hence the same workers who installed the jumper generally wired the necessary information into switch cross connect translations as well. Records were kept as pencil notations in ledger books or index cards.

Stored Program Control exchanges in the 1970s had teleprinter channels for entering and verifying translation information, which allowed centralizing these functions. In the 1980s the resulting conglomeration of Teletype machines were replaced with a more organized system called RCMAC which could more easily be coordinated with COSMOS, TIRKS and other Operations Support Systems.

Generally, RCMAC applied to 4ESS and 5ESS switches from Bell Labs (later Lucent, now known as Alcatel-Lucent). It centralized service order functions that previously were done locally. Basically, the RCMAC would hold any recently applied changes, be it a class of service change for a subscriber line, or orders for new phone lines, or disconnect orders. RCMAC was similar to the SERVORD application on Nortel DMS switches. Other telco changes would be applied to TIRKS, FOMS, WFA, etc. Acronyms varied from region to region.