However, there is a clear difference between the basic voice telephonydriven networks that are currently in common usage, and the datadriven networks that are gradually being introduced. No one questions that the level of demand for basic voice telephony, however transmitted, will continue to grow, but the underlying difficulty is that the explosion of demand for wireless-delivered voice telephony has already created a situation whereby networks are close to saturation point in developed markets. Hence, network operators need to introduce new, high-value-added services if they are not to see their average revenue per user (ARPU) decline as they seek out the remaining marginal customers who neither want to spend much at all on calls nor to buy expensive, unsubsidised handsets. The trouble is that the basic technology and networks developed for voice are inadequate for more sophisticated purposes, although it does have to be said that the development of the short message service (SMS) has proved to be an unprecedented and, in truth, largely unanticipated success based on existing technology.
