Campbell Scientific SDM-SIO1 Serial Input/Output Module - Manual (Page 16)

SDM-SIO1 Serial Input/Output Module
3.3.2 RS-485 Multi Unit / In Line Example
1 C1
2 C2 RS-485 0V for ground referencing
3 C3 To logger
4 G
5 +12V
6 G RS-485_0V
7 RX-A RS-485_Y
8 CTS-B RS-485_Z
9 RTS-Y RS-485_A
10 TX-Z RS-485_B
First RS-485
equipment
11 0V RS-485 0V
12 Z RS-485_B
13 Y RS-485_A
14 B RS-485_Z
15 A RS-485_Y
Second RS-485
equipment
As with all RS-485 configurations the use of termination
resistors is optional. They tend not to be required with shorter
cable runs and with modern slew-rate limited driver technology
(as used in the SDM-SIO1). NOTE
10