Question Receive wrong caracters from Serial Port

[Dominic36]

I need to communicate with a PLC in serial port. PLC sends 4 possible data: 0, 1, 2 or 3 (which are status).
My vb.net program uses IO.Ports.SerialPort class. When I read the data, the "1" and "2" are good, but the "0" and "3" are received as "?". I tried all the Read method (ReadByte, ReadExisting, Read, etc), it always give the same result. In HyperTerminal, it's fine.

I made a test program in another computer (Win 7). Test was perfect, I received all 4 status correctly. I ran the same test program on the original computer (Win XP) and once again, I got the "1" et the "2" but the "0" and the "3" was "?" (ascii 63).

anyone have an idea?? because I'm really puzzled here.

thanks a lot for your time and help

[Killer42]

I believe you should post this question in the VB.Net forum. This one's for the (very old) VB 4, 5 and 6, which work quite differently.

[Killer42]

P.S. It's not that anyone would refuse to answer your question here, it's just that you may not find people with the right expertise. I'm not familiar with VB.Net at all.