Title: Hardware Installation Guide.pdf
Install the resistors (provided with the module) as close to input device as possible. For cable length limitations, refer to the Specifications section.Input Resistor TableAlarm Zone Contact NCAlarm Zone Contact NONormal1K ± 10%2K ± 10%Alarm2K ± 10%1K ± 10%Fault - Line ShortFault - Line Open0 - 50 15K - ∞0 - 50 15K - ∞Fault - Foreign Voltage50 -750 1250 -1500 2500 -15K50 - 750 1250 - 1500 2500 -15K87.2Upstream CommunicationThe DDC uses Port 1 to communicate to the Intelligent System Controller.Port 1 is a 2-wire RS-485 interface, that requires the following type of RS-485 cable: 24 AWG (minimum) twisted pair (with shields). The main run RS-485 cable should be no longer than 4000 feet [1219 m], 100 ohms maximum (Belden 9841, West Penn, or equivalent). The drop cables (to downstream devices) should be kept as short as possible, no longer than 10 feet [3.048 m].The RS-485 communication is asynchronous, half-duplex, using 1 start bit, 8 data bits, 1 stop bit.Note: