This attached pdf file is OPE Series Option Manual.
Option is as following.
1. RS485 module.
2. Converter for RS485 to RS232C.
3. RS232C Cable.
4. USB Cable for RS232C.
5. Rack mount shelf.
6. Rack mount front cover.
7. Remote Voltage Sensing.
8. Rear Output Terminals.
9. Output ON/OFF Signal Control.
10. Analog Signal Input Control.
11. Analog Signal Output.
12. Display Resolution.
13. AC Input Changing.
14. Last Setup Memory Recall .
15. Windows Application.