Thanks for all you for guys posting your questions and answers here on this site. My case is like this: I connected a straight through cable (pin 3 and 6 are included) between rj45 port of 1747-UIC and SLC 5/01 port, cable lenght is 3meters. But Rslinx cannot detect the presense of SLC 5/01 at the RsWho. I sure that I configured the 1747-UIC correctly because after attempting to connect to SLC 5/01 which failed, I successfully connected to other DH485 device using the DB9 port of the 1747-UIC. My question now, is it possible for the DB9 port to still work if the rj45 port of 1747-uic is defective due to pin 3 and 6 connection?