United Systems corp nixie instrument

[Maurizio1957]

Hi everyone I'm looking for information on an old instrument  that I had from a friend long ago, I can't find nothing from the web. It has 4 nixie tube and  a neon lamp marked ERROR on the front panel. I'd rather have some information about it before plugging it in and seeing clouds of smoke....
It has a label marked United Systems corp  model 275ANS .
Many thanks to all, Maurizio IU5BEC