Keysight/agilent/HP 665xA Power Supply Link Port usable for PC control?

[fchk]

Hi!

I've got an HP 6654A System Power Supply, working fine. I'm looking for a way to control it remotely now, but GPIB is an expensive option. I found out that these boxes have "link ports" for connecting several  of them together with 6P6C modular cables so only one device needs an GPIB connection and the other ones get subaddresses. These link ports are connected in parallel an driven by an SN76176 RS485 transceiver.

My idea is to to use this port as a control port. A USB-UART adapter is easy to get, and I guess any RS485 transceiver will do the job. FTDI chips already have RS485 support built-in (DE/!RE switching).

Has anybody tried this yet and can give me any hints about bitrate or command set (SCPI or perhaps some binary protocol?)?

I don't have a second 665xA and a GPIB interface for reverse engineering it myself.



Happy Xmas!