Can't receive serial frome a board with pci 8433

[Rezak3022]

Hi, I have a problem. I designed a board and I have to send a packet through com port to the board and receive another packet from board through another serial port. The problem is that I can send the data but I can't receive. And I know the problem is not from board because I used another RS485 MOXA and it worked fine. I can send from PCI but I can't use it to receive. Baudrates and other things are adjusted correctly.

[Rezak3022 · Accepted solution]

I solved it. I had placed a 120 ohm resistor in the transmitter of the board and when I removed it, it work well.