Global System for Mobile Communication or in short GSM is a recent enhancement in the mobile technology.
GSM enabled mobile phones have a tiny chip and it is called as "SIM" card and it has been designed manually.
This SIM card has the potential to store a phone number and this number will be assigned by the service provider.
It also contains other information like phone book and also some other information regarding the registration.
There are various frequency bands used to operate the new GSM feature.
Frequencies of GSM There are distinct frequency bands like 900 MHz, 1800 MHz etc used in GSM mobiles.
Different frequency bands have been used in different countries.
The service providers of this GSM feature also varies from country to country.
The main thing to be considered while you choose a handset in this regard is the ability to support the frequency band of the service provider.
If your GSM enabled phone has the ability to work with any of the GSM service provider, it is said to be an 'unlocked GSM phone' with the support of the frequency band of the phone.
But it has to get the support of the frequency band of your handset.
But in practice, every GSM phones has been locked with a particular service.
In such cases you could not the get the service of other providers.
There are two frequency bands are used often.
They are: o Tri-band This type of band includes frequencies like 900 MHz, 1800 MHz and 1900 MHz.
You can use this tri-band frequency all around the world especially in the North America .
o Quad Band This type of band has the stuff to cover all kind of bands from 850 to 1900 MHz.
The quad band handsets have the capability to work with all kind of GSM service providers.
A faster GSM wireless service is EDGE.
EDGE is enhanced Data GSM Environment.
This network can deliver data up to 384 kbps speed and it is based on the GSM standard and uses TDMA.