Engine Computer ALDL to PC Link

I've been working on trying to get my ECU to communicate with my laptop computer. I've seen several sites where you can get cables (I built my own) and software to communicate to the ECU. Unfortunately, I can't seem to get it to work with my '95 RM Wagon. Has anyone else ever done this and gotten it to work?

I've gotten communication from the ECU, but the software doesn't seem to be able to read it - wrong format or something.

Update:
Using EFILive V4 and a 2-transistor ALDL cable I've gotten some communication. Now the problem is a "checksum failure". Is anyone familiar with this program?

The ECM is always sending some sort of data all the time and you have stop that flow, in order to connect. You have to "Disable coms" command to the ECM, wait for a few seconds, then select "Connect to ECM".

What software are you using to do this? I don't see the "Dissable Coms" in EFILive V4.

Update:
Good news all: We've gotten it to work. Using EFILive V4 and a two-transistor type serial interface cable I'm now able to watch everything (and I mean EVERYTHING) that the PCM / ECM / ECU is doing. All sensor data and all DTC's (trouble codes). Additionally, I'm quite close to being able to reprogram the ECU as well and override some of its functions.
This whole system will make troubleshooting so much easier when my car dies: not to bad for $4.42 worth of wire for connections.

If anyone would like more info on how it all works, let me know.

PS - This should also work for any Y,F or B body car with a 5.7L port fuel injection V-8 from '94 to '95.

Great!
What comm settings and which xml vehicle file do You use? I´ve compared gm276.xml and LT1_8051.xml and found small differences.
Does anybody know if LT1_8051.xml is a modified file with DS spec A276 as base? There are two different authors of the two files and they maybe just found same solution in slightly different ways? Files are in the "Vehicle data streams" folder of EFIlive program.
I am testing on my RM Estate -95 with Datamaster EE, Freescan and EFIlive. I also got the AutoXray EZ6000 before I made a 2-transistor PC-ALDL cable. The EZ6000 is great to check my other cars with but doesn´t have the longtime logging or programming features.

BTW I beat You pricewise, I had stuff lying around so my cable cost me 0 Swedish kronor (which is about $0 ;))

What software are you using to do this? I don't see the "Dissable Coms" in EFILive V4.

Update:
Good news all: We've gotten it to work. Using EFILive V4 and a two-transistor type serial interface cable I'm now able to watch everything (and I mean EVERYTHING) that the PCM / ECM / ECU is doing. All sensor data and all DTC's (trouble codes). Additionally, I'm quite close to being able to reprogram the ECU as well and override some of its functions.
This whole system will make troubleshooting so much easier when my car dies: not to bad for $4.42 worth of wire for connections.

If anyone would like more info on how it all works, let me know.

PS - This should also work for any Y,F or B body car with a 5.7L port fuel injection V-8 from '94 to '95.

I used the LT1_8051_m0_a for the vehicle file as a base - keep in mind, however, that this file has been modified slightly to work with my RM. I removed the "Heartbeat" data and changed the timing quite a bit.
Also, not every macro works yet - only the "Engine Data (Mode1_M0)" is operational, but I'm working on the others. I'll keep you posted.

I do have one more trial with Datamaster - then it expires. If you send me everything that you configured, I'll give it one last go. See if I can come up with something.

I´ll do a thorough test with Datamaster before sending the config since You´re on the last run.