Cellular Radio, Isdn Networks and Satellite Communications
Introduction In describing Cellular Radio, ISDN (Integrated Services Digital Network) and Satellite Communications we must first have a general understanding of the meaning of these forms of Telecommunications. After a brief explanation of the different forms, they will be described in more detail. Then the present and future roles in Irish Telecommunications will be looked at and some examples given. This will then lead to the conclusion. 1. What is Cellular Radio? Cellular Radio is the use of Technology using low powered radio transmission for transmission and receiving voice or data to a telephone network. Users can be stationary or mobile. It means users are no longer constrained to place to place as it is a "wireless" system. 2. What is ISDN (Integrated Services Digital Network)? ISDN is a system which provides digital capacity i.e. voice, video and data transmission in digital form, to be sent and received by a customer. Unlike stand alone services such as telephone, telex, fax and data communications, ISDN is a network which can offer all these services as a package in which a user can talk, exchange data, faxes and other documents at the same time, instead of having to use different networks for these services. 3. What is Satellite Communications? This is the use of orbiting satellites to relay microwave transmissions from earth stations to the satellite an to re-transmit those signals back down to another earth station by means of microwave transmission. Cellular Radio At present there are two types of cellular radio systems in operation in Ireland. These are: 1. TACS This system is an analogue system in which the voice is transmitted by radio from the telephone to the nearest base station in analogue form. Analogue systems are at present throughout the world but each Country would have different standards. So a user can not use the phone in a different country, also as the signal it transmits is in analogue form