mrbob, I understand what you are asking but must admit that I have not used one on our OBD I Vipers. I know that Actron used to sell a scan tool with freeze frame, etc that had OBD I and II cables. By my memory it cost at least a couple (or a few) of hundred dollars.
Something that I bought SEVERAL years ago for OBD II Vipers was purchased through Sean Roe...Ease Diagnostic Software...to be used with a PC. It worked well...as this was for an Purdue School of Electrical Engineering senior design project, pulling a variety of readings for a homemade HUD for a Viper. And before you ask...I am NOT an engineer, don't really know much about said things...just a project sponsor along with a really cool MIt-type PhD who had ALL of the brain power!!
Try the Ease website...and call Sean Roe.