Isolated or Non-Isolated Coax Sockets

Isolated and Non-Isolated - What's the Difference?
This is one of those questions that comes up with sufficiently little frequency that you have always forgotten the explanation each time it is newly asked. So, if only for my own sanity, here is the difference:

Non-Isolated Coax Socket
This is your standard coax socket. If you simply want to put a socket on the wall to plug your TV coax lead into this is what you need.

Additionally, this is the type that MUST be used for satellite installation (i.e. SKY), because a two-way signal is required, your SKY box does not just receive a signal but it also sends one back up to the sky dish, an isolated coax socket will block this return signal!

Twin Non - Isolated Coax Sockets
The twin non-isolated coax socket has two main purposes, the first is for use with SKY+ which requires two separates feeds from the dish to the SKY box. The second is for those people with a standard SKY installation wanting to send the signal to another room in the house.

Isolated Coax Sockets
In very simple terms, an Isolated Coax Socket is like a non-return valve! It lets the signal through from your aerial/dish but does not allow any sort of return signal/current. The main application for this type of socket is where a communal dish or aerial is used, such as in a block of flats. The isolated socket stops interference from receivers (TVs, Digiboxes and SKY boxes) from spoiling the signal that the rest of the users receive.