Jones Motrola Tach Question ?????

Can anyody tell me what the key and switch is all about on this tach. I have looked around on the net and found these tachs but none of them had the key. Whats up with it?

 

wonder if it locks out the telltale reset button?

 

Thanks for the info guys...

 

What....you didn't like my answer to this question you asked a half hour earlier??

http://www.jalopyjournal.com/forum/showthread.php?t=401472&highlight=jones+tach

Terry