Intel OPEN (660) 120/140/150 II - Manual (Page 153)

User Manual version 2.1
OPEN (660) 120/140/150
9-143
D: RS-485 Programming
The RS-485 is software programmable. I order to
program the RS-485, a program writing I/O port address
204 (hex) needs to be written first. The output data is a
value of RS-485 TX/RX status. The data function
definition is listed below:
RS-485
SD0 SD1 TX RX
0 0 Disable Enable
0 1 Enable Enable
1 0 Disable Disable
1 1 Enable Enable
Note: data D7~D2 have no bits concern