How to organize RPM client command?

I want RPM Managed by a Timer that can control the port turn on at 8:00 and turn off at 18:00 every day.So I want to develop a client using JAVA. But I don’t known how to communicate with RPM,I can only connect it by serial port using jcomm.jar.

The RPM only has a serial port with a simple ASCII cmd line. It is not a network controller. We support it through our TS and/or Console server (CM/Passport) product lines.

This kbase article shows the options available via the cmd line: