The 1785-KA3 PLC-2 Family Communication Adapter Module by Allen Bradley is a communication adapter installed on any slot (except the furthest left) of the 1771 I/O chassis, which links the PLC-2 family processors to a Data Highway Plus (DH+) Network. The 1785-KA3 draws 1.2 A backplane current at 5 Volts DC. It has an interface port for connection to the PLC-2 Programmable Controller using the Data Highway Plus Processor cable and a Data Highway Plus drop-line, and for connection to the 1784-T50 Industrial Workstation using the Program Panel Interconnect Cable. The 1785-KA3 has 3 sets of switches: the Data Highway Plus baud rate switch assembly, the write options switch assembly and the node address group switch. These switches determine the mode of connection with other nodes on the network. This unit supports most PLC-2 family processors, and the module is keyed to the backplane by connecting the band between pins 4 and 6, 22 and 24 of the top connector. Its temperature range is between 0 and 60 degrees Celsius (32 to 140 degrees Fahrenheit) at 5% to 95% non-condensing relative humidity; its storage temperature is between -40 to 85 degrees Celsius (-40 to 185 degrees Fahrenheit).