Hi Kevok,
Yes it does, I control a receiver, HD DVR, DVD player and TV and the remote gives me all the options that each of the other remotes do. It lets you set up both Activities adn Devices. Activities being 'Watch TV', Watch DVD etc, which lets you turn on/off the right equipment with one click based on the activity. The device setup allows you to set up each device and their functions. In my case, all the components I have were part of the database so I didn't have to set up any custom keys, but in addition to that you can 'teach' the remote by using the original remote and 'transfer' the commands to the Harmony 550. Once the setup is done, all the functions of each of your components should be available with just this one remote.