Television Shopping in PHP

The history of cable television in the UK is briefly summarized, and the current communications environment is described, focusing on the factors affecting the provision of broadband services. Existing cable television technology in the UK is examined. The modern networks that have adopted a conventional tree-and-branch framework have typically been built as 450-MHz systems (or are under consideration for upgrade in this level) with a capacity for 30 channels, adequate for the presently available program sources. The latest systems are looking to 550 MHz, to allow for future expansion; such a network might carry 34 PAL channels and 6 MAC channels at maximum capacity. For the most recent franchise awards, the 860-MHz systems are now a consideration. Some switched star networks, aimed at allowing interactive services, have also been built. The likely course of development of cable television in the 1990s is outlined, and the three network types that seem to be the main contenders-coaxial tree-and-branch, distributed-star, and passive optical networks-are discussed.