NEC Microcontrollers and serial

Does anybody here know anything about NEC microcontrollers, and specifically the SBI mode of two wire serial they support?

I'd like to indicate that it looks like I2C, but it is not, and the 2 are not compatible.

http://www.manualslib.com/manual/109641/Nec-Pd750004.html?page=172#manual

This link explains it, but I wondered if anyone here has any experience with it.