MEFI-1 DLC connection cable

peos

Recruit
Joined
Sep 16, 2015
Messages
5
Hi,
I'm looking for info on how to build my own adapter cable for the MEFI-1 DLC to PC serial (RS232 or RS422) connection. I can find the pinout on the DLC, pin B is "test" and G is "serial data". I'm missing some pieces though, does anybody have this info and willing to share:
What is the voltage level on this connector, is TTL (5V) or is it 12 Volts or something else?
Is "serial data" data out from the ECU into rx-data on the PC and "test" the other direction or is it something more tricky to it than that?

I'm looking to hook up a PC with TunerPro just for fun, want to be able to read GPH without investing loads of $. Guess I need something to do on the boat during the long cold winter as well :)

I've been building serial interface adapters before, so it shouldn't be too hard, but need to know these things since I no longer have access to proper analyzers for serial communication :-(

Regards
PeO
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
peos, Have you search the the web for the pinout on both RS232 and RS422 communications? Being older type communication protocols, there should be tons of pictorial diagrams for those pinouts. The RS232 should be easy to find. I don't know about the RS422 setup, but it shouldn't be hard to locate either. Have you actually searched for RS232 to RS422 conversion circuitry? Could be a DIP or SMD chip available for such a conversion. :noidea:
 
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