HI Gerard, a standard ethernet cable will work. Like Tom said, do not get a crossover cable. Also,
do not plug the control module or the thermostat into an actual ethernet network!

If you run into trouble or would like to order a standard 50 ft replacement or a custom length cord from us, give us a call at 315-299-3589.
Coaledsweat, the Coal-trol does not use standard bell wire for the thermostat, we use RJ-45 sockets and standard 8 conductor ethernet wiring. However, we do use low voltage, in the area of 12VAC.