Symax 400 unable to load project

I am unable to load a ladder logic project into this Symax 400. It begins to rack address and then I receive a transmission error 74 after about four adresses are loaded. I can access the PLC fine, it's just that I can't load the ladder logic into it. I am using sfw375 and entering the programming port on the front through a Symax rs232-rs422 converter.

My PC is running W2K. Is my PC too fast, or do I need older programming software like sfw374? I am able to load the ladder logic and the labels offline into sfw375.

Any assistance would be much appreciated.
Thanks,
Eric

Wow the old symax. I have some software the dos version and a windows version. It is archived on my attic computer. I'll dig it out(or search for it) you'll have to give me a few days. I also have some old Symax cpu's and I/O cards. Bullet proof (robust) stuff. Now I also had a symax prog cable somewhere.

I have the DOS version of sfw375 and I have the Symax RS422 interface cable, but I just can't seem to get the ladder logic to load.

I have an older Toshiba laptop with Win95 loaded that I have used to do some Symax 600's, but it died on me a few weeks ago. I wonder if that may not be my solution? I'll open that thing up and have a look inside.

Any other ideas? I really need to get this ladder logic loaded into this Symax 400. It is used in a conveyor system in a major airport here in NYC and it the only backup they have.

Thanks,
Eric

Only experience I had with Symax was using a serial port for the programming. No 422. This was on a pretty new PC that was also running Wonderware and AB stuff.

Make sure you really have a serial port. Windows is funny about that. If you're running RSLinx, make sure it's off. Sometimes you get a conflict with RSLinx, but there's no message that says so.

I am pretty sure it is a communications port issue.
The old DOS programs assumed the comm port would always be available, some of them even used the clock pulses from the comm port in their error checking. But after Win95 Microsoft decided comm port servicing would no longer follow their old standards.

You might try a DOS emulator.