Ok, finally found some time to test again with the machine... My findings:
With my cable your software didn't do anything. Obviously my cable is incorrect. By checking the help of your program I noticed it decribed a cable pin layout, slightly different from what I had (but still not the same as the one you gave in this thread).
Code:
PC TC
RD(2) -------- SD(2)
SD(3) -------- RD(3)
ER(4) -------- DR(6)
SG(5) -------- SG(7)
DR(6) -------- ER(20)
RS(7) -------- CS(5)
CS(8) -------- RS(4)
I rebuilt the cable and tried again with your program. I sent a program from the Brother to the computer and as by a wonder for once the Brother didn't give the DR SIGNAL OFF message. Good... On the computer it was obvious there was data received, but the software crashed on it with error 13: Type mismatch. I have absolutely no idea what might be causing this. But the most important thing was that there actually was some sort of communication between machine and computer.
Thinking the issue with my cable might now be solved, I switched back to my TCEditor software. I sent a program from the machine to the computer... And tadaah: no error message, but a lovely "Completed" messagebox.
Then I tried to send a program from the computer to the Brother. The traditional DR SIGNAL OFF error message appeared on the screen: transfer failed. But... Checking the machines memory I noticed the program was actually submitted to the machine. I chose a program number that was still open and after transferring - even though the machine states it failed - the program was in the machine's memory.
At first sight I couldn't spot any differences between the program on the machine, but the error message made me suspicious. So I resubmitted the program from the machine to the computer enabling the Check option (verifies machine data with computer data). Somewhat expected it said there were differences (but the stupid software won't say where).
I also rebuilt the cable according to your alternative cable pin layout, but that gave exactly the same result.
I tried to get your program working, but it always gives me the earlier mentioned error message.
So to summarize: With the cable pin layout I gave earlier in this message I got data transmission from machine to computer working. From computer to machine seems to working more or less, but it always gives this error message and the sent data is most likely corrupt.
In terms of usability I'm just as far as you... I can send the memory of the machine to the computer, but I can't get the data back into the machine. But the fact there is corrupt data sent back is promising. If I could just resolve the DR SIGNAL OFF issue...