The Minister with responsibility for broadcasting, Ms de Valera, yesterday unveiled ambitious plans for Ireland's entry to the digital revolution. But it is not yet time to discard the old television in the corner. It could be many years before digital television forms part of our everyday lives. Indeed, it could be more than 15 years before the current system, known as analogue, is finally switched off. That said, the pressure on the consumer to invest in the new technology is set to intensify. Only 15 years ago we had never heard of CDs, home computers or mobile phones.Once a significant number of viewers can receive digital television, the Government will find itself under increasing pressure to switch off the old system so that valuable frequencies will become available to commercial users like mobile phone operators.RTE has emerged as the real winner in yesterday's announcement. It had sought Government approval to establish a company with a strategic partner to develop the digital transmission system.A number of financial interests, including some cable companies, had made their opposition to RTE's potential role known to Government. But now the State broadcaster is free to begin finding a partner, which will presumably supply the capital while RTE supplies its site and transmission sites, masts and technical know-how. What the Government announced yesterday was a system called Digital Terrestrial Television. It will supply 30 channels grouped into what are called multiplexes. Each multiplex will have five channels. RTE will receive one multiplex, giving it a further three channels on top of RTE 1 and Network 2.It has already indicated that it would like to operate a 24-hour news channel, probably in partnership with an international TV news operator, and an educational channel.Digital will also allow it to operate local "opt-outs" allowing local news and some local programming. It also wants to operate a "catch-up" channel, allowing viewers to see programmes they might have missed earlier in the week.It is assumed that the other multiplexes will be sold off to those wishing to deliver new services to Irish viewers.Technically, digital TV simply means transmitting a signal in the computer language of zeros and ones. In layman's terms, the signal simply takes up less space, allowing far more to be transmitted. When the signal arrives in your home a set top box or digital television unscrambles the signals, allowing you to view the programmes.The main benefit of digital is the increase in choice, but it also promises much better picture and sound quality. The signal should be as clear and strong for the person living farthest away from the transmitter as for the viewer living underneath it. The broadcasting world has been waiting rather impatiently for yesterday's decision. Now it has been announced, viewers should expect change to start taking place quickly.Sky Television has already launched some digital channels and the BBC is poised to begin. Irish cable operators want to offer up to 400 channels - if they can find the content - via cable. Although digital terrestrial television will allow 30 channels to be received anywhere in the State via an ordinary television aerial, once we have a set top box and its capacity to unscramble signals we will then be able - should we choose - to buy extra television via cable or satellite.This week, Cablelink in Dublin has announced new services via thecable. Before long it will also be possible to receive the World Wide Web via cable. Digital will also allow a huge development in radio, with the promise of hundreds of channels, including many specialist programmes.Some pundits refer to digital television as the biggest change since the advent of colour. Others go further and say it is the greatest broadcasting revolution since television itself.For the ordinary viewer there is little doubt that watching television will never be the same again. In the interim, the costs of digital television and set top boxes will fall. Set top boxes will be available for about £200 and digital widescreen televisions - which were selling at £1,500 - have already dropped to a £1,000. They could be as low as £500- £800 by Christmas.From the start of digital broadcasting all current channels will be broadcast simultaneously in analogue and digital. How soon analogue is switched off will depend on the Government. The pressure to do this will come from commercial interests who require the spare frequencies for commercial use and who want to increase the sale of digital televisions. On the other hand, there could be some political resistance: politicians may be wary of switching off the system and leaving even a few people without access to television. The recent row over the TV deflectors just shows how political television can be.