art phones as stated earlier can also hog a disproportionate amount of radio access bandwidth, a composite of the application bandwidth and signalling bandwidth needed to keep the application and multiple applications alive. This does not matter if there is spare capacity, but if a network is running hot (close to full capacity) then voice calls and other user data sessions will be blocked or dropped. When blocked sessions or dropped sessions reach a level at which they become noticeably irritating to the user then customer support and retention costs will increase and ultimately churn rates will increase, which is very expensive for the industry. As this paragraph was written (17 May 2011) Vodafone's annual results were announced18 Vodafone's annual profits received a smart phone boost despite an overall fall in net profits of 7.8 per cent. Despite a £6 bn+ impairment charge on operations in its European "PIIGS" markets (Portugal, Ireland, Italy, Greece, Spain), a 26.4 per cent boost in mobile data revenue made a significant contribution to its overall profit of £9.5 bn for the year. This suggests that smart phones are unalloyed good news for operators. However, this is only true if the operator can build additional capacity cost effectively. This may of course include network sharing or acquisition. However this is achieved it is wise to factor opportunity cost into any analysis of device economics. A device is only profitable if the income it generates is greater than the cost of delivery. 5.3.1 Standardised Chargers for Mobile Phones Anyway, if a user's battery goes flat at lunchtime, at least he/she will soon be able to borrow charger to substitute for the one they left at home. 2011 was the year in which a common charger standard was agreed using the micro-USB connector already used for the data connection on many smart phones and finally overcoming the frustration and waste of multiple connection techniques. Hurrah we say. 18 http://www.vodafone.com/content/annualreport/annual_report11. Making Telecoms Wor