Our latest Mars soiling sensor units (810230-20_01 and higher) use Wi-Fi for user setup communication.
Older models (810230-01, 810230-20) require a wired Ethernet connection to the user's laptop. This Ethernet connection is made using an RJ45 to 4-pin M12 Ethernet cable.
The required cable is available in the Configuration Kit 810276.
However, you may also purchase this cable from Amazon, for example at this link.