TDA's are great. Panasonic finally has it together for certification to stop the Internet bootleggers and Joe Blow working out of his house with no overhead, no insurance and no support back-up and no trainer (i.e. trunkers). I hate going out to bid a system with my time and fuel and lose to someone selling the product at almost my cost. The trunkers in our area are just happy to sell systems at cost and make their money on the install. I won't even price a system over the phone anymore. Panasonic finally heard us on this issue. And, the wireless cells are great.