network + phone over power?

vansaint

Greetings,
A neighbour wants both ethernet and phone connections in a separate building about (guessing, may be farther) 50m from the house. He already has power there. Someone told him to check out ethernet over power and phone over power devices. I had never heard of the latter but did a search and found a device called Instajack.
However, I don't know whether two pairs of such devices could be compatible, i.e., if the ethernet and phone adaptors would use different frequencies and work simultaneously on the same power line. Also, I am quite sceptical anyway since, apart from the distance, the propagation of the signal must depend on how the wiring to the other building relates to that in the house. Basically, I doubt the signals would get there for one reason or another, but I don't know enough to say whether it is worth his buying the widgets to test that.
One thing I thought of was that if he got the ethernet-over-power to work, he could get a wireless DECT-based device to supply the phone socket. But I think the distance might be pushing the range of that option.
Does anyone here have experience of such a setup, or know of some other alternative to running a pair of wires out to the other building that's more likely to work?
Thanks

vansaint

Update: Having done a bit more research, it seems the InstaJack (phone over power) frequencies overlap those of ethernet-over-power devices at the low end. So it seems the option of having them share the power line is out, even if one or the other would work alone.

Xantia

Best run a cat 5 or better cable to the new building