kci (kahn communications, inc., the company that invented cam-d) uses as one of its main selling points that some older transmitters are not directly upgradeable to transmit hd radio. it is true that older transmitters may lack the transmission purity needed to support hd radio's digital transmission standard, but more recent transmitters are more likely to be capable of upgrading to transmit hd radio. cam-d is said to work with a wider variety of existing transmitters, which is a selling point for smaller broadcasters with limited budgets. the price of the cam-d hardware is $65,600 as of july 1, 2007.