<![CDATA[UNIT-RS485]]>Anyone tried using the UNIT-RS485 module to connect a UHF-RFID tag reader to an RS485 system? The module is typically used to connect TTL serial IO to RS485 but I see no reason that it should not work in reverse, except that it doesn't. I see the serial command on the RS485 side but nothing on the TTL serial IO side.

]]>https://community.m5stack.com/topic/4573/unit-rs485RSS for NodeFri, 10 Apr 2026 12:41:27 GMTWed, 31 Aug 2022 00:00:11 GMT60<![CDATA[Reply to UNIT-RS485 on Tue, 06 Sep 2022 23:05:24 GMT]]>Felix, you were correct. All that was required was a cross-over of the white and yellow leads in the cable. Thanks.
...Brian

]]>https://community.m5stack.com/post/18558https://community.m5stack.com/post/18558Tue, 06 Sep 2022 23:05:24 GMT<![CDATA[Reply to UNIT-RS485 on Wed, 31 Aug 2022 07:49:10 GMT]]>Hello @BrianAtNRC

do you see the serial commands on the TTL serial IO side when you disconnect the UHF-RFID unit? If yes, then I suspect the serial lines to be the issue. Since you are connecting two units you cannot use a standard (straight) Groove cable. You need to modify it so the serial lines are crossed out. TX from one unit needs to go to RX of the other unit and vice versa.

Thanks
Felix

]]>https://community.m5stack.com/post/18508https://community.m5stack.com/post/18508Wed, 31 Aug 2022 07:49:10 GMT