i have just acquired a brand new pair of tp link. plugs.on the box it as tl-pa4020p kit.i have googled this ,but dont understand what it is supposed to do.is it something i can use.any help would be appreciated.It allows turning your home wiring into a means for network communications, but this technology is not PERFECT. It might work in some buildings and homes and not other etc. I have seen nothing but troubles with these devices. It seems like the ones that did sort of work had to be on the same leg of the building so if you have another room that is fed power from a different 120VAC leg then it might not work so well or not at all. If the other room where the PAIRED device is to be plugged in is on the same leg on your service then it might work ok or might be spotty where it works and then acts up without warning.

These devices are for people looking for a way to pass a network connection from one room to and send it to another like a communication bridge. If you got these for free the prior owner might have thrown them away because they didnt have success with them. 

I'd avoid using them unless you have an application that really needs to use them. Secure Wireless Networking is the way to go or hard wire Cat5 or Cat6 to a switch connected to internet connection that offers network connections to multiple rooms etc.  Each one plugs into an AC outlet and has an RJ45 (ethernet) socket. You use them when you don't want to string a long ethernet cable between 2 PLACES in your house. I think they work better in British houses, where we have a ring circuit, rather than some other countries where they have separate branch circuits. I have a pair of these to connect our smart TV to the cable modem/router, because my wife said "no" to a long ethernet cable. Also cheaper than the Samsung wi-fi adapter needed for the TV. They have worked fine for 5 years. I can stream 1080p video from my NAS DLNA server to the TV without any buffering or stuttering. From time to time one or other goes to sleep and you have to power cycle it, I would say this has happened 2 or 3 times in 5 years. my personal experience, having come across them a few times, is if possible, use something else.
their attraction in theory is 'plug and play' but in practice they can be difficult to setup and high maintenance.
I use the same philosophy with these devices as I do wifi, if possible go ethernet, but if you can't, alright give them a go.

I think Salmon is right, it depends largely on how the home is wired.

they were popular a few years ago, before the latest gen of dual and tri-band routers that have far superior coverage and penetration, elimination the need for these devices. Quote from: Mark. on December 11, 2017, 01:44:28 PM

my personal experience, having come across them a few times, is if possible, use something else.
their attraction in theory is 'plug and play' but in practice they can be difficult to setup and high maintenance.

they were popular a few years ago, before the latest gen of dual and tri-band routers that have far superior coverage and penetration, elimination the need for these devices.

time for a new PVR