Class II data interface.....

Hello again... :lol: ....I was wondering if anyone has information about the Class II data systems used on many vehicles.I believe it is the SAE J1850 protocol.I want to know some information about these systems because I like to tinker with my new truck,and I would like to build interfaces like this one...**broken link removed** know that there is ready made units available for this purpose,but I would like to build some just for the fun of it.If someone could point me in the right direction as far as literature on the subject goes,it would be much appreciated,thanks.....

https://www.cardlabs.com/CardLabs_obd2.htm

Scroll down two thirds of the page for plenty of
J1850 VPW (GM style) Part Datasheets and App Notes


Worth getting up to to speed on folks.. OBDIII is looming
draft proposals suggest the use of radio transmitters to report
the vehicles carbon monoxide output..doubt they will stop there.

WOW... :shock: ......lots of info here.Has anyone made any projects to tap in the multiplex line in there cars???I think a new area for these types of projects would be cool.... :lol:

Plenty of projects about for reading the OBD data, Speed , Rpm, Battery voltage,Injector timeing, Air Intake Temperature.. the list goes on.
Writing data to the vehicles computer can also be done, giving one the ability to tweek performance just like they do in race cars, alas have found no circuit/ software available freely.