I am new to automotive electronics and have been reading about OBD and CAN bus. what i undnerstand is OBD port is kind of a standard now, so my questions are
If I get control of OBD port through my telematics device, I can largely control all ECUs / if not monitor vehicle parameters?
From a telematics integration point of view, do i need to ensure access to each bus CAN, LIN, MOST etc. to gain full access to all ECUs or mere access to OBD port is enough ?
What about cars/trucks that are pre CAN bus era, how do we monitor them from hardware perspective ?
I understand there are other ways to monitor vitals such as through mobile devices, but want to understand if OBD port is not present, can we integrate the telematics system with vehicle someway ?