The suggestion is to use one pair of the CAT cable for Data and Data GNDand another pair for Vcc (5V) and GND.
There are allot of places...For example: http://1wire.org/index.html?target=p_2.html&lang=en-usand: http://www.fischer-net.de/hausautomation/haustechnik/1-wire/26-1-wire-belegung-kabel-stecker.html
I don't like parasite mode - extra 5Vcc is more stable and the CAT cable has enough wires
Sure, the idea is to also shield the 5Vcc - but nowhere i found what to do with the second GND.It only makes sense to me like i draw it. If you only connect one side you have a big antenna.
I already made the temp sensor from my circuit on a 0,32x0,98" veroboard (damn that 0805 SMD ferrite bead is small).Now i need to solder the sensor to the CAT cable (for the in-floor heating) that i can lay my laminate floor and then i haveno longer access to it.Unsure what to do with the GND.
Cat 5/6 cables make sense if your devices are quite far away, they are a waste of material if the distance is less than half a meter in a not so noisy environment.
beside the sensor
Try it in an environment as identical as possible to the final installation