Submitted by chinavision
The world of mobile phones is a confusing one, particularly for those wondering how to start a cell phone business, as GSM frequencies and GSM phones work in some parts of the world and not in others. So what is the background behind a GSM network? The GSM network was first suggested by a group of European technicians and policy makers in 1982. It didn't take long for consumers and phone makers to adopt the new network after it first emerged in 1991, and wasn't long before there was growing GSM coverage in an increasing number of countries.
The GSM world grew quickly. There were more than one million subscribers spread over 70 carriers in 30 countries by the end of 1993. Not only did the new GSM mobile network send and receive all of its information digitally, making it the first 2G mobile phone to be developed, it also gave users a great deal of freedom on what they did with it. For the first time they were able to send short written messages to each other for a fraction of the price of a phone call. They could change their carrier and/or go to a different country without getting a new phone. All they needed to do was to take one GSM SIM card out and replace it with another GSM card, and they were in business.
But, as the unknown powers of the world decree, things shouldn't be that easy, and GSM frequencies set by most of the GSM networks had already been assigned to other purposes. So, in a situation very similar to TV viewership, and people with surveillance systems, a phone that worked in Sussex England wouldn't pick up anything in San Antonio in the US. Basically it wasn't a case of one GSM frequency that fits all. As a result, many cell phone manufacturers created cell phones that could work with more than one band, and some working with as many as 4 bands. Still this doesn't mean there weren't unanswered questions, and people were often left asking the following questions:
What is GSM?
GSM, Global System for Mobile communications (or the Acronym formally known as Groupe Spécial Mobile) is a wireless transmission standard used for mobile phones and, recently wireless modems. GSM and CDMA differ because GSM networks use a SIM card to store all the necessary information to send and receive calls where with CDMA phones, everything is kept on the phones. If you are looking at how to start a cell phone business and you don't have thousands of dollars in working capital, GSM mobile phones will probably be a better option than CDMA as they won't be attached to a particular carrier and don't require you to be licensed to a particular provider to sell unlocked cell phones. Another reason to select GSM over CDMA is that it will open up the potential customer base for each phone. Unlocked GSM phones can be used with any GSM network. To date, there is no such thing as an unlocked CDMA phone. When it comes to cell phone plans, most providers (especially those in the States) love CDMA phones because it locks their consumers to them.
Why do GSM phones have more than one band?
GSM Phones come with more than one band so that they will work in more than one country, as there is more than one GSM frequency, and they are not universally transmitted. As a result, wholesale cellphone manufacturers make GSM and GPRS phones with multiple cell phone bands, so that they can work in multiple countries. Most cell phones work on two, three or even four bands. Quad band phones are the most flexible as they can be used all over the world and are often called international phones as a result.
How are multiple band phones defined and where will they work?
Multiple band phones are usually defined by how many GSM frequencies they can operate on, and usually come in different categories - dual band, tri band and quad band. It is important to remember the different type of bands as it could mean the difference between your customer getting a high performance phone that they're happy with, or them getting a shiny and costly paperweight. Dual band phones works with two GSM frequencies and, depending on where the phone is made