The OPTI-6100 DS1 Tributary Module (DS1M2) multiplexes/demultiplexes one STS-1 into 28 DSX-1 M13-mapped circuits using the signal from the backplane of the OPTI-6100 chassis. These circuits are made available through the champ connectors on the back panel of the OPTI-6100 chassis and are usually routed to a DSX panel.