ve-year or three- to five-month or three- to five-day horizons can destroy longer term competitive capability. Additionally, it is an inescapable fact that global scale is now more or less an exclusive precondition of commercial success in the telecommunications sector. Arguably only one country is large enough to have sufficient economies of scale to sustain any kind of nationally specific telecommunications technology policy. Previous attempts to protect local markets have, however, proved disastrous, the impact of nationally specific Japanese standards on the Japanese vendor community being a relatively recent example. 'Making Telecoms Work - from technical innovation to commercial success' is an all embracing title for an all-embracing attempt to bridge the traditional gap between engineering and the business planning process. It is an absolute truth that hugely ambitious commercial plans can be invalidated by appar- ently trivial technical details. This brings us to Chapter 2. Part One User Hardware Physical Layer Connectivity 2.1 Differentiating Guided and Unguided Media This chapter explores the dynamics that determine the deployment economics of copper, cable, fibre and wireless networks both in terms of bandwidth efficiency and power efficiency and explores some of the metrics that are presently used for comparison and could potentially be used in the future, for example cost per bit, bits per Hz and joules per bit. All of these physical layers use a combination of frequency or time multiplexing. Cable copper and wireless all use a combination of nonorthogonal or orthogonal frequency, phase or amplitude modulation. These techniques are also becoming, and will become more widely, applied in the optical domain. Telecommunication delivery options can be divided into guided and unguided media. Guided media includes fibre optic, coaxial cable and copper or aluminium twisted pair. Unguided media include free-space optics, fixed wireless (one-way and two-way), portable wireless and mobile wireless. A first-orde