Written by Sean McDonald
May 2000

Dual-Band refers to a digital network and mobile handsets ability to transmit and switch (automatically) respectively between two different frequency bands on that same or other network.

The traditional GSM (Global System for Mobile Communications) networks found in Australia and the world operates on the 900 MHz frequency range. However, operators in many countries, including Australia, are introducing GSM networks operating on the 1800 MHz frequency range as a cost effective method for fast and flexible capacity increase as a result of the growth in mobile phone usage.

The world's major mobile handset manufacturers, Nokia, Ericsson etc. have already produced handsets that have Dual-Band capabilities and it seems that most of the future handsets will have this advantageous functionality.

The advantage of supporting a Dual-Band network is increased capacity but for users of mobile phones, the benefits of using a Dual-Band handset are quite enticing. As previously stated different countries operate on different frequencies with most of the world operating on the 900 MHz frequency range, the United States operating on the 1900 MHz range and an increasing number of countries including France, Germany, Switzerland, the UK and Russia operating on the 1800 MHz frequency range. If you wish to roam, that is travel to international destinations and still able to use your mobile phone, mobile phone number and be billed at home, you may encounter problems that can be alleviated by using a Dual-Band phone.

If roaming to a destination that uses the same GSM frequency as your home operator then as long as your home operator has a roaming agreement, exchanges of billing information, with the foreign network you will have no problems using your mobile phone. However, if you travel to a country that operates on a different GSM network frequency than your home network operator you will not be able to use your existing phone. To use your existing number you have to transfer your SIM (Subscriber Identity Module) card to a phone of the right frequency called SIM-roaming. This is at considerable cost to time and money because either a phone of the correct frequency will have to be purchased or hired. But if you own or use one of the many Dual-Band phone handsets available, either the 900/1800 MHz or 900/1900 MHz frequency ranges, no such problems will be encountered and mobile phone usage will be the same as that at home. Also, recent additions to the mobile market have seen the introduction of handsets that operate on all three, 900/1800/1900 MHz, frequency ranges.

With most of the latest and future mobile phone handsets already supporting Dual-Band capabilities, the prospect of having to endure the hassle of SIM-roaming seems close to elimination and the truly global mobile phone is now a reality.