a century and is still very much in use. The price differentials is not usually very high, and there is a lag in time prime reason for this is that, as stated earlier, older technologies before consumers take advantage of these differentials. If the con- usually move from developed countries to the developing coun- sumer is an infrequent user then price comparisons may not be tries, which suits their economies. possible at all. For example a consumer on the move, using fixed and mobile telephones within various locations, such as hotels, It is instructive to look at telegraphy, as a technology and as a would not be able to obtain an accurate price comparison of these service. Prior to its invention it took many weeks for messages to be services if they were supplied by competing service providers. taken over relatively short distances, usually on horseback and sail boat. The first use of telegraphy was optical, and the word was coined Services and technology by the French Chappe brothers who founded a 145 mile optical telegraph line between Paris and Lille in 1794. Towers with tele- The two major elements of the telecommunications model of Figure scopes and mechanical semaphores were used, coded messages 11.1, are the customer demand for services and the underling tech- being passed from tower to tower with people doing the translation. B-ISON Sonet/SHD Videotext Packet switching Cellular mobile Digital telephony Mobile telephony Circuit switched data Telex Analogue telephony Telegraphy Figure 11.8 Service and technology introductions 11/14 The telecommunications industry The Moscow to Warsaw system opened in 1838 and had 220 There are many application technologies, a few of these being stations with almost one and a half thousand operators and support given in Figure 11.9. Most of these are relatively new, such as SDH staff (Andrews, 1989). and ATM, whilst others have been established for longer but are Electrical telegraphy was invented by Samuel Morse and Alfred developing, such as ISDN into broadband ISDN and