Mobile phones are bit like walkie-talkies (or radios) in that they need to "tune in" to a special frequency.
In actual fact they tune into a range of frequencies also known as Bands and some mobile phone handsets are smart enough to tune into more than one band:
- the handset can tune into two bands
- the handset can tune into three bands (usually GSM900 / GSM1800 / GSM1900 but please check)
- the handset can tune into all four bands
To understand “Bands” we also have to understand “Networks”. TravelSIM and most of the world’s mobile networks work on GSM including Australia, however there are also other types of networks available.
A simple way to think of this is comparing networks to language - if your phone speaks GSM it can't speak 3G and it won't understand the 3G network.
Hint: See more on mobile frequencies to know what band or frequency your mobile handset can "pick up"?