Specifications

12 Chapter 2 Documentation Number: ESP902-2303 Manual
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph [phone] – Fax [phone]
RS-422 Connections
In the RS-422 mode, TXD lines are outputs, RXD lines are inputs. Connect
the TXDB(+) line to the RXDB(+) line of your device, and the TXDA(-) to the
RXDA(-) of your device.
If Flow Control is set for RTS/CTS, connect the RTSB(+) to CTSB(+) of your
device and RTSA(-) to CTSA(-) of your device. Connect from CTSB(+) to
RTSB(+) of your device and from CTSA(-) to RTSB(+) of your device.
If connecting to Receive Only RS-422 devices, connect from TXDB(+) and
TXDA(-) to the receive pairs on all your devices.
Ground is signal ground and provides a common mode reference for the RS-
422 Receiver and Transmitters.
The RS-422 mode can be used for full duplex 4-wire RS-485 operation
provided that the ESP902 is acting as a sole master connecting to all the
slave devices, and all slave devices share the Receive signal lines to the
master. Set Flow Control for none, and omit connections to RTS/CTS line
pairs.