Hi all,
I’ve been having a lot of “fun” with a couple of [Modbus controlled dimmers which don’t play nice with some RS485 interfaces. I’ve tested them on a [Monarco Hat’s RS485 port, a [StarTech ICUSB2324852 and most recently a [Sparkfun BOB-09822. Of these, only the externally powered (5V) StarTech interface provides reliable communication. Other Modbus RTUs on the same network work fine with all three. But the StarTech interface is my Swiss army knife for serial comms and belongs in my toolbox, not permanently installed in a wiring cupboard. I suspect the issues I’m seeing are related to the dimmers having higher voltage thresholds on the A/B data lines than the Monarco Hat and Sparkfun board provide. My question is, can I modify the Sparkfun BOB-09822 somehow to get 5V signalling? Grateful for any suggestions!](https://www.sparkfun.com/products/9822)](USB to RS232/422/485 Serial Adapter - Serial Cards & Adapters | Add-on Cards & Peripherals | StarTech.com United Kingdom)](https://www.monarco.io/)](DLD1248-4CV-MODBUS)