COSMOS was introduced in the 1970s after MDFs were found to be congested in large urban telephone exchanges.
It assigns terminals so jumpers need not be so long, thus leaving more space on the shelves.
COSMOS orders are usually coordinated with RCMAC to ensure that translations match wiring.
With good computer records, jumpers are often left in place for reuse when one customer replaces another, resulting in a great reduction in labor.
More modern modular MDFs were developed around the same time called COSMIC (Common System Main Interconnecting) frames.