ced telecommunications wiring needs and costs. signal and communicate to each other to establish the call. This is However radio coverage over the entire service area must be good not a feature of the earlier analogue standards. enough to ensure that the probability of a call being set up exceeds These two ETSI standards are considered by many to be com- 99% otherwise users expectations, based on the performance of plementary in terms of the market expected to be served and the wired telephones, will not be met. entry time to that market. CT2/CAI has been optimised to serve the Telepoint is a service provided to cordless handset owners from residential and small (business) cordless markets with potential to cordless base stations located in public places, e.g. railway stations, open up the high capacity business market. DECT, however, has shopping precincts, fast-food restaurants etc. This is a basic public been designed from the outset to meet the demands of the very high communication service for the less migratory more localised sector capacity cordless office with roaming and in-call handover as stand- of the travelling market and thus does not compete directly with the ard features of the specification. It also has the capability to be wide roaming mobile cellular network. Hence a handset purchased appropriately configured for the residential markets. Both have for use in the home and/or work place can also be used to gain access telepoint capability. to a telepoint service whilst the user is in transit between them. 49.2.2 Main service principles 49.3 CT2/CAI digital specification 1. The system must make provision for voice and non-voice These specifications are described in Swain (1990), Holmes and transmission. Swain (1990) and Evans (1990). The FDMA/TDD principle of 2. All radio channels are available to all users and applications, operation of CT2/CAI is shown in Figure 49.1. Duplex transmission hence channel licensing and regulation is not needed. is provided by transmitting in time interleaved burst m