You could retrofit a more modern computer in there. Probably even reverse engineer the radio system and replace it.

This would have been done by an enthusiastic high school student with both programming, electronics, maybe some RF knowledge too. Radio amateur? I find these stories kind of sad. Clever system built by someone talented, at a low cost -- replacement with a modern system costed in the millions. Those talented people still exist but they wouldn't get a look in with most RFPs.