Trace panel beep beep beep

I have a 2002 Holiday Rambler Imperial DP. Low miles well maintained. I have a Trace inverter/charger which is 10 years old, The panel above the passenger seat that controls the inverter/charger no longer works. It does however beep about 7 times a second  and the charge light flashes at the same rate. The battery full light is on steady. The window states "system status float charging". The window will change to waiting for AC, or Inverting. None of the buttons allow any changes.

Trace is long gone, Xantech bought the company, but no longer supports any trace units. I have looked for a replacement for the controller and found a few on ebay, Salvage units 3to$400 no guarantee.

My question is this; all of the inverter controllers I have encountered use the "phone jack"  style connecter. Is there another brand or universal controller I could use? My only other options replace the inverter charger and the controller, or wait for it to die?

If you need more information let me know.

Thanks for help

Jim