Is there a feature code that will show the software revision on a display phone?

on the DX80 No

Thanks for the information, I had looked in the manual and found no reference but was thinking that it might be an un-documented feature.

System programming:
Resource
KSU Revision

There is no feature code.

Bill is correct, but it actually depends on the version. I believe they introduced that option in F28 or A33. Prior to that, you'd have to look at the sticker on the chips or connect via PCDBA.

Justin