The OPTI-6100 DS1 Tributary Module - VT - Enhanced multiplexes / demultiplexes one STS-1 into 28 VT1.5 mapped DS1 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.