2Pack TTL to RS485 Adapter Module, 485 to TTL 3.3V/5.0V Signals Serial Port Power Supply Converter with Indicator Lights

This product has worked for me so far, but I am only transmitting data. Another reviewer stated, "Pay attention to the photo, it has the color coding exactly per the photo". The boards that were shipped to me came with a cable color coding of Black, Blue, Yellow and Red. When plugging this provided cable or harness, VCC is Black, TXD is Blue, RXD is White, and GND is Red. So, the mfg./shipper is using cables with different colors. Reading the other reviewer's comments, it was a bit confusing. I guess in short, believe the printing on the board for VCC, RX, TX and Ground. Switch the cable colors if you have the time and tools to do so.

Pay attention to the photo, it has the color coding exactly per the photo, but you want red to be the +5 and the black to be ground, so I removed three of them and corrected that. Then I found the yellow wire which I didn't touch to be open, when they crimped the terminal on they sheared off the copper wire, so no connection was made. Lucky I had new terminals and a crimping kit to fix that. I could not find a schematic of this, but the RC time constant for the auto shift between transmit and receive is too short. As I could see with my oscilloscope receive noise, when that line should have been quiet. A small update, these do work OK, but the screw terminal quality, has issues with clamping onto a soldered dipped stranded 24AWG wire. This is bad enough I won't buy anymore of this model. As well the phillips screw driver head is so poorly made that I can't find a screw driver that will bite into them without much force to keep it from slipping.