Advanced police scanners are able to monitor state-of-the-art digital trunking radio systems. These scanner radios also have the most complete set of features which radio hobbyists and professionals use and love. There is a learning curve to programming these scanner radios and using these features, Scanner Master sells books to help you master the gear. The public safety agencies in certain areas require advanced police scanners, others do not. The only way to be certain whether you need an advance police scanner in your area to visit the web site www.policescanners.net or by emailing or calling us at 1-800-SCANNER to check.