It means that there are companies out there who can add a TV tuner to your comand for you and also enable DVD playback. The OEM tuners are not cheap, circa £700 from memory. The labour to install it and then program your comand to accept it will not be cheap either. I would estimate the whole lot is going to cost you circa £1500.
Try sending a PM to Miro and ask him what he will charge to do it for you when he comes over in july.