The OPTI-MX DS1M Module multiplexes/demultiplexes one STS1 into 28 DSX-1 circuits using the signal from the OPTI-MX OMM modules. The 28 DS1 circuits are M13 mapped. These circuits are made available through the champ connectors on the back panel of the OPTI-MX chassis and are usually routed to a DSX panel.