Telephony's future freed from the wire
CELLPHONES are just one of many telephony technologies that are transforming the way that people communicate. In future, mobile phones will become far more versatile and use several different methods to get calls to and from subscribers - wherever they happen to be in the world.
The world of telecommunications is a pretty jumbled affair because it's an environment that has evolved over time. The world's telephone system is largely interconnected by wire.
Within that framework are several technologies. There is the plain old copper wire network, essentially unchanged for decades, the newer and faster ISDN (integrated services digital network) and even high-speed leading-edge fibre optic networks. These systems on their own, however, are not much good for mobile phone users.
Portable phones require some sort of system whereby the telephone signal can be freed from the wire system and transmitted through the air to wherever a mobile phone happens to be. That technology is largely based on the same principles of two-way radio. Most mobile phones are just extremely sophisticated walkie-talkies that can communicate with the international telephone grid.
The first mobile phones cost a fortune and were plumbed into cars. "Portable" handsets were available but they had to be lugged around like a briefcase. Then smaller analogue cellphones became available and networks sprouted up in the US and other parts of the world.
South Africa has followed Europe and Scandinavia by adopting a superior digital cellular system known as GSM, or global system for mobile communications.
Cellphones work on cells, little stations connected to powerful antennas that dot cities, towns and line the major national roads. As a cellphone user moves between cells, so the network hands the caller over to the appropriate cell.
The cellular network is connected to Telkom's wire-based grid which is connected to the telephone system that spans the globe. That makes it possible for a cellular user in Laingsburg, say, to call anywhere in the same town, South Africa or the rest of the world.
The problem with cellphones is that they work only where there is cellular coverage. Cellular base stations cost a lot of money and network operators place masts only in areas where they believe there are enough subscribers to warrant doing so. That is why future generations of cellphones are going to have to combine several sets of technologies to offer better coverage.
Cellphone manufacturer Motorola recently unveiled a cellphone that can use both digital and analogue cellular networks. This means the phone can be used in countries like the US, where there is large analogue coverage, and SA where there is only digital.
Another manufacturer, Ericsson, has a phone that combines cellular technology with another called DECT in one handset.
DECT (digital enhanced cordless telecommunications) is another radio-based cordless telephone technology that allows telephone networks to be set up in rural communities or in businesses without having to lay down expensive copper cabling.
But the system that has the potential to gather the most phone subscribers in its net is a satellite system. Because satellites have such a large footprint or coverage area, they are ideal for telecommunications. There is a caveat, however - satellite signals are weak so aerials on handsets tend to be huge, making communicating by satellite expensive.
That could change. Already phone manufacturers are working on ways to combine satellite telephony with current mobile networks like GSM. While the phone is in GSM coverage it uses that network but as soon as it moves out of range, the call is handled by a satellite system.
So, while right now it's possible to say you couldn't take a telephone call because you were not at your desk or you were out of cellular coverage, early next century there will be no excuses.
Quite literally, if you so wish, you can be contacted wherever you are on the face of the earth.