Comment by KaiserPro

We have a voip system for the house, mainly because its one floor too tall to shout up and easily be heard.

Each of the kids has a really old cisco voip phone (I got 8 for £35).

There is a quick dial menu which connects too the loft, kid1, kid2, shed, living room. I also have an extension for my mobile.

That works for keeping everyone in touch and save a lot of "WHAT DID YOU SAY?".