What does this do?

[Mw Roofline]

A complete novice to multiroom but I've got 3 rooms in the house with ceiling speakers. I now have a multiroom amp and I've been offered one of these cheap but I don't know what the hell it does or how I will use it.

Can anyone explain in laymans terms what it does

http://www.harmankardon.com/estore/hk/us/products/ABH-4000/ABH 4000_HK_US

Thanks

 

[Lucid]

Unless you've already installed the matching Harman Kardon keypad system then that hub device is useless to you.

There are various ways to do multiroom. One of them involves a central comms room in your home that houses the amplifiers and sources and switching gear. The system is controlled from each room by means of in in-wall keypad. Basic ones just allow source cycling and volume control. More sophisticated ones talk to a medial server and have the ability to display track listings and playlists. Harman Kardon makes something along these lines using a communication protocol called A-bus. That device forms and extension to an existing system. But on its own its a an expensive paperweight no matter how cheap it is.