Custom daisy-chain RS-232 cable for CR tuners and modualtors, passes data communication for up to nine units. First DB9F connects to control port on system, the rest connect to tuners. Tuner connectors marked for units1-9 the cable sequence must match the tuners's unit #. Standard configuration provides 6' to control port, 12" between units, user can specify different lengths. Pricing set for 2-3 units, 4-5  units, 6-7 units and 8-9 units.