Remote Control Bus provides the connection for Volume 8, Select 8, Volume/Select 8, Voltage Control Box, and Logic Box external control devices.
Each NEXIA device can support any combination of the controls mentioned above. Up to 12 controls may be connected to each NEXIA device, on a daisy-chain 'network', with a maximum cable length of 1000 feet (300 meters). A Remote Control Bus Hub allows multiple branches on a control network.
Cabling and power for an RCB network can be calculated using a program (NexiaRCBCabling.hta) found under Program Files/Nexia/Ultilities. Controls are wired in parallel (pin-for-pin), using 5-conductor data grade cable (95~120 ohms nominal impedance; 16 pF/ft. max. capacitance; 65% min. velocity of prop.).
Recommended cable: Gepco 18/22AXL, Liberty AXLINK, Liberty CRESNET, or equivalent
(use data pair for Hi & Lo; use power pair for + & -).
The 'network' requires termination at each 'end' for proper operation. All controls (and NEXIA) include either a termination switch or jumper strap. These terminations should be disabled (switch out or jumper removed) on all devices except those at the two extreme ends of the network. (See wiring diagram below).
A control network may be wired with the NEXIA device at one end, and a control device at the other end, creating one continuous run. In this case, the NEXIA device would have the 'term' switch engaged (in), and the control device at the other end of the network would have the 'term' switch engaged (in) or jumper installed. All other controls, between the NEXIA device and the last control, would have their 'term' switches released (out) or jumpers removed.
If a control network needs to service two areas which are in opposite directions from the NEXIA device, a network with two separate runs can be created. This type of network actually remains as a single run, but is configured with the NEXIA device in the middle. Therefore, only the controls at the two extreme ends of the network would have their 'term' switches engaged (in) or jumpers installed. All other controls (including the NEXIA device), between the two end controls, would have their 'term' switches released (out) or jumpers removed. (See network diagrams below.)