For those of you with 8192 baud ECM's..... How are your experiences with your interface?

I had connection problems with the 2 transistor one, but I might have screwed it up or something... Just wanted to get some input. Please post your experiences with either the 2 trans or the MAX232 circuit (whether bought or built)!

 

A max232 circuit will always be better then a 2-transistor. The reason is that it creates the proper voltages for the rs-232 interface. A 2-transistor setup doesn't always provide the proper voltages to the laptop serial port. This is one of the reasons it may work on one laptop but not another.

RBob.

 

excellent point. Just makes me curious how others can get by selling the 2 transistor interfaces?

eg - http://www.aldlcable.com/

 

My homebuilt MAX232 has worked perfectly on both 7730 and 7749 ECMs.

 

Ive tested my 2 transistor cable on 3 different ecms no problem. 165, 730, and a 93 S10 TBI ecm no problems. It was a total of like $3 in parts from radio shack.

 

have you tried it on different computers?

 

My notebook was specifally bought to scan so no. Its an IBM thinkpad with a pentium 266 processor. It works great for my needs so I have no reason to use any other computer.

 

I always had problems with the 2-transistor type, even when used on a buds car, so Im using the MAX232 chip configuration. Using software, I designed my own printed-circuit-board. I bought the raw materials for the board and built my own. Looks very professional and like a commercial product. Not like the crappy pre-drilled boards at Radio Shack. Everything is in place, just waiting on my capacitors so i can finish it.

Also, the MAX232 works with either 160 or 8182 baud without having to change components. You can also incorporate a switch to change between 10k resisotr, a short, or an open from A to B at the ALDL.

Oh, for those wondering what it costs.

15 3" by 4" copper clad boards---$8
30 sheets transfer film---$10
Software---FREE
Schematics---FREE
Iron---FREE Everyone should have one of these already
#66 drill bits, pack of 20---$8
MAX232 chip---80cents
Diodes---1 cent for 100 Thanks eBay!!
Transistors---10 for $2
Capacitors---$12 for 400 variety pack
Already had the resistors


I bought in bulk so I can make more if needed, and for future projects. So when considering costs per board Im looking at right around $4 if you include shipping for everything.

 

The crappy predrilled stuff at radio shack seems up to snuf besides its in a black enclosure and you cant tell its home made anyhow. Ive used it on a few of my buddys cars and they seem more amazed at the dataloging coming from my notebook rather than the looks of the actual cable. I dont even think they realize the box even exists. I never had to do anything special to make it work so I dont know what the big deal is. Linked up to my 165 the first time i hooked it up. I have a few datamaster uni files saved at home from the S10 TBI unit.