pgmfi.org

http://www.ff-squad.com/tech/ecu/obd1.mugen_xg5_2.jpg

Looking to the board, it connected to CN2, anyone know this ecu used what additional board there?

it looks like a dataloger but the little board looks to be made by the same maker of the ecu board so is it a factory option ,i love to know about this to

This is RS232 inferface.

in english

Sorry,

TTL to RS232 converter

what like a dataloger i dont know technical terms

^^ yes.

the chip is basically a MAX232 --> http://en.wikipedia.org/wiki/MAX232
a serial datalogging adapter for TTL based communication.

so the little board was made by Denshigiken so was it was a factory part . thats weird

specially made for mugen, highly likely they were doing their tuning the same way we are now.

Actually i always asking my self, what is CN2 pin 5 for... Looking to mugen TTL > RS232 dengkenshi used all CN2 pin

so what were they using it for

the green wire looks like it runs to a LED, which is likely used for a visual confirmation for communication status.
Hope to have a few minutes later today to check this theory.

All though I'd be shocked if the pioneers that discovered the operation of CN2 didn't all ready research this...

You want the schema of this interface
(I suspect the answer )

well since I have no time tonight for the test, YES!
(all though I think I all ready know what it's going to look like)