WIZ750SR-EVB-485 , No serial Tx or Rx

My goal is to send and receive simple serial ASCII text between a uP based device to a LAN connected PC by using a WIZ750SR-485. See diagram below.

I have verified (with a scope) that my uP device is sending a simple stream of 20 ASCII characters once a second at 115.2k baud, 8 bits, 1 Stop bit and no handshaking, to the WIZ750SR using RS-422. Verify in the picture that the RS422 slide switch position. I have successfully connected to the 750SR using the WIZnet config tool as indicated in the next image. Using “RealTerm”, a serial capture program running on the same PC, I cannot verify any of the ASCII characters from the 750SR over the LAN. I have also tried to send characters from the PC using RealTerm to the 750SR, but nothing seems to arrive on the 422 Rx line.

Any Ideas? Does anyone see anything wrong with my config?


I think you have to change the subnet mask in Network configuration as

If that doesn’t work, I need a packet capture file using wireshark(freeware program) for analysis.