The firmware revision on the DX-80 is F15. This applies to the mainboard on the base and the expansion cabinet. Also the SLT card is F15. The earlier F12 expansion had problems with the F15 main cabinet and vice versa.

On the DX-120 the revision on all three is F18. Traditionally you need the same firmware throughout on TECOM products. I haven't tried it yet but why bother? The main cabinet cost is relatively low when purchased in packages. Replace the DX-80 cabinet with a 120 and expand it. Since all the old cards may be used the cost is relatively low. Put the DX-80 in inventory for service on other DX-80s. The only minor issue is the old PC8 voice mail but if you know what you're doing it can easily be set up for the DX-120.

--Bill.