Bought a couple of these recently, just now got them working over a 30M alarm cable, ie no twisted pairs. The usual got ya, had TX and RX around the wrong way to the Pico. Used the Core Electronics Low/High level converter between the device and the Pico.
Connected the RE & DE pins making it like a direction signal rather than an enable. Drive this low and the device receives, set high to transmit. It was pretty easy to set up using UART of the Pico and one GPIO for the direction.
My intention was to use these to send sensor data to a main unit for a weather station. But I think I will go with more expensive units that incorporate some isolation and line protection. Still these offer a rather cheap way of sending data that does not involve WiFi or other radio transmission. Very happy with how these units are performing so far.
Cheers
Jim
