Specifications

Chapter 3 Connecting peripherals 21
RS-232/422/485 serial port connections
RS-422 is commonly used for two-way communication between
two devices, whereas RS-485 is used for communication between
a single master and a network of slave modules.
Before you use the RS-232/422/485 port, you will need to select
RS-232, RS-422 (the default) or RS-485 mode. Set jumpers JP20,
22, 25, 26, 27, 28, 29 and 30 according to the following table:
RS-232 RS-422 RS-485
JP20 1 - 2 2 - 3 2 - 3
JP22 Open Short Short
JP25 Open Open Short
JP26 Open Open Short
JP27 Open 1-2 2-3
JP28 1-2 2-3 2-3
JP29 Open Short Short
JP30 Open Short Short
Pin assignments for the DB-9 connector RS-422/485 are as
follows:
RS-422/485 connector pin assignments
Pin Signal
1 TX - or send data - (DTE)
2 TX + or send data + (DTE)
3 RX + or receive data + (DTE)
4 RX - or receive data - (DTE)
5 Ground
6 RTS - or ready to send -
7 RTS + or ready to send +
8 CTS + or clear to send +
9 CTS - or clear to send -