Don't know it an issue of running our of connectors, as much as wanting to identify a different standard and baud rate from the older ECMs. When they switched to the 7427 ECM, it was a major advancement in the evolution of computer engine management.
If you want to really read what your engine is doing, you can purchase a connector/adapter
here. Yes, you can build one for less than 20 bucks, but time you buy a USB to serial adapter and find one that actually works, you are better off to just buy the complete table.
Download TunerPro RT software
here.Download a datastream definition file, (so the software knows your ECM)
here.
IRV2