er for computer systems. Customer sys- codes. Encryption. Spread spectrum systems. References. items. Power management systems. Maintenance and costs. Mobile power plant. Power plant accommodation. Building engineering 15 Telecommunication cables services. Reliability and cost. Future developments. References. Introduction. Symmetrical pair cables. Coaxial pair cables. Line Acknowledgement. plant for copper cables. Optical fibres. Optical fibre cables. Cable design. Line plant for optical cables. CCITT standardised optical 25 Software systems in telecommunications fibre. Future developments. References. Acknowledgements. Overview. Stages in the software lifecycle. Software design tech- niques. Lifecycle for each software design technique. Software 16 Network management simulation. Programming languages. Testing procedures. Software The need for network management. Network management struc- development environments. Software configuration management. tures. Network management hierarchy. Network management func- Software cost estimating. Software quality and reliability. Refer- tions. Trends in network management. The OSI model. OSI network ences. management concepts. The Telecommunication Management Net- work. The Simple Network Management Protocol. Bibliography. 26 Radio spectrum management Introduction. Frequency assignment. International frequency allo- 17 Antennas cation. International spectrum management. National frequency Types of antennas. Basic properties. Generic antenna types. Spe- management. Efficient spectrum utilisation. References. cific antenna types. Antennas used in communication systems. References. 27 Radiowave propagation Introduction. The radio frequency spectrum. Free space propaga- 18 Analogue modulation tion. The propagation medium. Low and medium frequency ground Introduction. Amplitude modulation. Frequency and phase modula- waves. High frequency skywave propagation. Terrestrial line of site tion. Pulse modulation. Acknowledgements. References. propagation. Over the horizon transmission