GSM (Global System of Mobile comunications)

What is GSM?
GSM (Global System for Mobile Communications) leads the world as the fastest growing, most reliable and advanced digital technology available in the marketplace today. GSM provides integrated voice mail, high-speed data, fax, paging and short message services capabilities. GSM customers enjoy secure communications, and GSM offers unparalleled call privacy and fraud prevention. As members of the GSM Global Network, GSM subscribers can use their phones at home, across town, across the continent, or around the world (except for with country specific SIM cards). GSM operates on the multiple spectrum frequency bands used around the world - 1900MHZ, which is used in North America and 900MHz and 1800 MHz for other locations. Different mobile phone networks operate at different frequencies, which means that if you wish to use your mobile phone outside your home country, you generally need a handset that supports multiple frequency bands. Make sure that the celluar phone you are interested in is compatible with the GSM band of the country you will use it in. As a general Guideline:
Dual-band - A dual-band phone operates at both the 900 MHz and 1800 MHz spectrum. Dual-band works in Europe, Africa, Asia, Australia, New Zealand and much of South America.
Tri-band - A tri-band phone operates on three frequency bands, 900 MHz, 1800 MHz and 1900 MHz, allowing you to use it in Europe, Africa, Asia, nearly all of North America, Australia and New Zealand.
Quad-band - A quad-band phone allows you to roam almost anywhere globally. It covers the 850 Mhz, 900 MHz, 1800 MHz and 1900 MHz frequency ranges. Many countries in South America only have 850 MHz GSM service while both 1900 MHZ and 850 MHz GSM services are supported in the USA. 99% of all countries use the GSM standard. WE believe eventually GSM will be the only cell phone standard in the world.
The GSM network provides the best digital wireless voice quality in the world today.
GSM Quad Band
GSM, the short form of Global System for Mobile Communications, is a leading digital cellular system. GSM mobile phones operate on narrow band Time Division Multi Access (TDMA) system, which allows eight simultaneous calls on the same frequency. It was first introduced in Finland in the year 1991 and by the end of 1997 GSM service became the accepted standard in over 100 countries around the world and is now the de facto standard in Europe and Asia. The TDMA technology is a multi-access digital transmission system by which, multi-users can access a single radio frequency (RF), without any interference. It works on providing individual time-slots to each of the users within each channel.
To this day, there are more than more than 690 GSM mobile networks across 213 countries and consists of 82.4% of all global mobile connections. According to statistics available there are more than 2 billion GSM mobile users in the world, with China having the largest users with more than 370 million, and Russia following with 145 million users. While US have 78 million, India has 83 million using the GSM service.
A mobile phone can be a bewildering affair for a traveler. It is mostly incompatibility with the network of your visiting country, since every country in the world has different frequency band of operation.
Almost all parts of the world operate on GSM technology, except USA and Canada. Originally GSM operated at a frequency of 900 MHz, which is being continuously upgraded and now works on 1,800 MHz service. With a GSM phone, you can access service in 212 different countries. Some of the mobile phones available in the United States and Canada operate on GSM, but most of them are of a different frequency band. The GSM service available in North America is of a totally different frequency of 1,900 MHz and sometimes 850 MHz, which is different from the standard of 1,800 MHz. Not all countries in the world use the standard 900/1,800 MHz GSM. The exceptions being, Canada, Mexico, Japan, Korea, and some Central/South American countries, with some limited coverage of the standard GSM networks.
Today, mobile phones have become a part of daily living. We often wonder how we ever lived without them. Whether you are traveling on business or on a holiday, mobile phones offer incredible services during your journey. However, they also present some challenges, when you wonder if that mobile phone you have will work while you travel from one place to the other.
There are three bands on which the mobile transmission is based on, with different countries operating on a different frequency falling under different bands. Today, quad band mobile phones take away the fear in you, relieving you from that worry, if your mobile phone will work in UK.
The obvious convenience of having a mobile phone makes you feel safe where-ever you are, with the facility that it has to quick-access for help when you need it and talk to the people important to you. It is one of the most economical and essential life-long product in anyone's life today. Think about those olden days when you had to make a call from your hotel room. Think about the bill that you paid, just for your telephone calls. Now you have a mobile phone, a partner to your daily life. You can already feel the difference. Today, many of these phones are being offered with exceptional plans that may include, free airtime, cheaper long distance charges and in some cases cheaper international roaming charges. In India, for example, service providers have started to offer life time incoming calls on pre-paid sim cards of your mobile. Realising such a benefit, you feel comfortable that atleast you are available on your mobile phone. Prices are dropping every month, which started with a huge investment when mobile phones were first introduced.
Let us look at why all mobile phones are not compatible.
There are two explanations to this reason. The first one being that all service providers in this world do not operate on the same radio frequency band and encoding services. Therefore, when you travel to UK, your phone might not be compatible with the kind of frequencies that the service providers offer.
The second point is a bit complicated. To enable a mobile phone from the United States to work in UK, the service providers in UK, or vice-versa, must have a cross-billing arrangement with one or more service providers in the other country. This cross-billing arrangement is a commercial deal between the service providers of the two countries, which results in allowing roaming in your mobile phone. In some cases the roaming facility in your phone, needs to be activated by your service provider in US. If this is the case, then, you have to have roaming enabled before you go out of the country. This arrangement falls under International Roaming. The same is the case with National Roaming. Therefore, you need to have such a phone, which would accept all the three bands the service providers operates on in this word, and such a phone is the one with quad band features. Dual band phones on the other hand would work anywhere in the world except the Unites states.
Let us look at some of the problems with mobile phones in the United States. If you are in US and you have a mobile phone which you would like to have the international roaming facility, your best bet would be to sign up with service provider who provides GSM. The two major GSM service providers in US are T-Mobile and Cingular, with the consideration that AT&T has now been merged with Cingular.
This sounds like a perfect solution. You now have one phone which works all over the world. If you have decided on such an arrangement, it must be what you want. But, you need to consider that GSM service is quite limited in US. That takes you back a bit. No, there is no solution for that. To have your way, you will have to maintain two mobile phones, one with a major established network in US and a second; having the GSM service with roaming features.
GSM is a state-of-art technology, offering fax capability and Short Messaging Service (SMS). Most of the service providers offer e-mail to SMS feature, making it possible to receive important announcements and information over your mobile phone, viz., receiving flight updates and breaking news alerts. Many offer quick connectivity to ISDN services, there by allowing fast data transmission. The latest generation offers Global Packet Radio Service (GPRS), which enables you to connect to a high-speed data communication channel, faster than 9,600 bps.
We have discussed the limitation of GSM services available in US vis-à-vis roaming. We have also said that in order to over-come this limitation and avail international roaming as well, you would have to maintain two mobile phones, one with a major established network in US and the second; having the GSM service with the roaming features. Instead of maintaining a second phone, mobile phone rental service is also available. There are many outlets who would rent you these phones with perhaps certain terms, viz., you would need to get your relevant sim card from them.
The GSM has made roaming between operators a very common affair, facilitating the users to carry their mobile in almost every part of the world. GSM is considered to be a second generation (2G) mobile phone system.

What is a SIM card?
The SIM (Subscriber Information Module) card - a.k.a. "smart card" - holds all of a subscriber's personal information and phone settings. In essence, it is the subscriber's authorization to use the network. It also holds the phone number, personal security key and other data necessary for the handset to function. The card can be switched from phone to phone, making the new phone receive all calls to the subscriber's number. For more information about SIM cards, go to our Prepaid SIM Card FAQs page.

Where in the world can I use my GSM phone?
At the end of 2000, the GSM Alliance had signed agreements with 217 international carriers representing more than 100 countries. GSM customers can use their phone service at most of the tourist destinations in the world including Europe, Asia (except for Japan and Korea), Africa, the Middle East, Australia, New Zealand, India, China and other countries and most major cities in the United States and Canada.

Will a 900MHz GSM phone work in the United States?
In most cases, no. 900MHz GSM services will work in Washington DC only. Since Washington DC is home to many foreign diplomats, special considerations have been given to the area. In the US, 1900 GSM service is available in most areas. Please be sure to check local carriers such as Voicestream or Cingular wireless to verify that there is coverage in your area.

What does unlocked mean?
Most cell phones that you would purchase are locked, meaning that you must use the provider's service for receiving phones calls. Since ours are unlocked, you can simply purchase the cell phone and purchase the SIM card elsewhere.

Are your GSM cell phones unlocked?
All our GSM mobile phones are FACTORY unlocked - they will work with any GSM SIM card from any country on earth - so you needn't be tied into any specific carrier or contract. Every time you change the SIM CARD the GSM phone becomes whatever the new SIM CARD is. I.E. a new telephone number, memory for credit, the ability to work in the new country etc.
If you got your CELL PHONE from a USA carrier (such as T-MOBILE, AT&T etc.) very likely it is LOCKED to their service and can't be used with any other service provider in the states or overseas. To determine if your phone is locked call your service provider and ask them. If they will not unlock it for you our phones are FACTORY UNLOCKED with all features always available, we rent and sell these phones. Often if your carrier will unlock your phone some of your phone's features are permanently disabled.
If you purchase a SIM CARD from us you will SAVE as much as 95% of what you can expect to pay for your outgoing calls through American companies such as Pacific Bell, AT&T, T-MOBILE, Cingular, GTE etc. For example, calling the states from England is just US 7 cents a minute. Incoming calls (from any and all countries on earth) are free for you to receive in 99% of all cases.

Where can I purchase a SIM card?
We offer prepaid SIM cards on our web site. To view our selection of prepaid SIM cards as well as recharge cards for existing SIM cards. Check our Prepaid SIM Card FAQs page for more information about SIM cards.

When will I get my phone number?
Unless indicated on the country specific web page, phone numbers are given when you purchase your SIM card. If you purchase an country specific SIM card, you will get an overseas number pertinent to that particular country. Swisscom international prepaid SIM cards have a Swiss phone number assigned to them.