Newb trying to reconnect

[Arnold Wiegert]

Hi all,
After losing my ISY some time ago after a decade or more of having it run my lights etc, I moved to an installation of Home Assistant (HA) running on a small dedicated PC. Because things worked so well for so long, I now find myself quite rusty in trying to replace some of my wall switches and possibly reworking/updating some of the setups.
Over time, much has evaporated from memory and some notes have been lost.
As part of restarting my work on home automation, I was hoping to be able to monitor the traffic sent to & from the devices to help me refresh my memory and understanding.
The problem for me right now is how to get started. One of my options seems to be to use insteon-terminal, but I am lost on how I would go about connecting to the hardware.

The HA PC connects to the hardware via a 2413U USB Dual-Band PowerLinc interface.
I do have a second Serial Modem 2413S, though I don't know whether it still works or how I could test it without upsetting any of the rest of the current hardware.
My current hope is to perhaps use this second PLM as a test interface to the Insteon power line network via insteon-terminal. An alternative might be to tap into the USB modem hookup with a small USB hub and then listen/patch in commands, also using insteon-terminal.

One of the challenges for me would be to try and (re)scan my Insteon devices and their status/state.

Any help or advise on this project will much appreciated.