portant since a human operator is not available to Kirvan, P. (1992) The perks and pitfalls of opting to outsource, compensate for loss. Delay is less important unless the system is Communications Networks, May. waiting for an acknowledgement. Martin, W.J. (1991) The European Community's STAR Pro- Interactive retrieval services are the other half of messaging gramme, European Business Review, 91, (2). services, and usually consists of retrieving information from a Patel, V. (1992a) Realising Broadband: The Regulatory Hurdles, database. Telecommunications, March. Distribution services are subdivided into those with user control Patel, V. (1992b) Speeding toward a single market, Communication- and those without user control. Examples of services without user S International, January. control are broadcast television or radio. In distribution services Patel, V. (1992c) Pan-European High-Speed Networks: Fact or with user control the user has presentation control, for example Fiction?, INTE NET, April. selecting the material for viewing from a broadcast. Examples are Payne, M. (1991) Telecommuting: the need for broadband, Com- weather forecasts and stock price broadcasts. munications International, October. Piggott, J. (1991) THe status of CSTA, Communications Interna- tional, December. 11.6 References Schwarz, T. (1991) Public Procurement in Telecommunications, Telecommunications, 1 January. Sharma, P. (1991) Opening the European Network for Services, Aamoth, R.J. and Smith, R. (1991) Competitive markets, Communi- Telecommunications, May. cations International, October. Sweeney, D. (1992) The coming of satellite-based mobile phone Anerews, F.T. (1989) The Heritage of Telegraphy, IEEE Commun. service, Cellular & Mobile International, Winter. Magazine, August. Varakin, L.E. (1989) The macroeconomics of telecommunications, CCITT (1.88) Part C of the Report of the Seoul Meeting (Jan. 25 - Elektrosvyaz, 2, pp. 34-39. Feb. 5), Study Group XVIII, Report R55(c). Walters, R.E. (1992) The missing link: Computer-supported tele-