[Nut-upsdev] Liebert ESP-II protocol

[Joe Krahn]

I see there has been some Liebert work here recently. I have a Liebert 
UPS that has no USB, just RS-232. I reverse engineered the ESP-II 
protocol, at least as far as normal MultiLink monitoring goes, which was 
pretty simple. The protocol provides a table of parameter types and 
index ranges. So, I can read and (if I dare) write the parameter tables.

We might be able to share info between serial/USB to help figure things 
out. The nice thing about serial is that I can hook up a null-modem 
loop, feed values to MultiLink, and see how it replies.

Joe Krahn