Roberts Gorden CORAYVAC Installation Manual page 103

for 38.4k, Port 2, and Modbus.
7. Connect the communications port and jumper wir-
ing to Port 2a.
SECTION 12: I
NTEGRATION WITH
EIA-485, 4-wire
Wiring specifications
• A dedicated 24 AWG to 18 AWG twisted pair
• wire (EIA-485)
• 2000' (610 m) for 76.8 kbps
• 3000' (914.4 m) for 9600 bps, 19.2 or 38.4 kbps,
before needing a Repeater
• Devices should be daisy chained and not star
wired
• If the controller is at either end of a network seg-
ment, connect a terminating resistor (P/N
10061018) to the I/O Pro 812u
Note: Use the same polarity throughout the network
segment.
EIA-232, 2-wire
Connect to Tx, Rx, DTR, DCD, and Gnd using three
wire termination with pins 3 and 4 jumpered. Wiring
must go plus-to-minus and minus-to-plus, Gnd-to-
Gnd.
B M S (BMS)
UILDING ANAGEMENT YSTEM
99