A mobile phone, also known as mobile phone or cell phone, cellular phone or hand phone, sometime shortened to just mobile, phone or hand, and sometimes just cell, is basically a portable phone that able to make and receive calls on a cellular signal network while the user is traveling within a specified telephone service region. Cellular phones are not considered to be a public safety device, because they can only work within the specific coverage area of a specific company. Although you will be charged more when roaming outside the coverage area, this usually isn’t more than the difference in charges for making and receiving calls within your home country. There are two basic types of mobile phones: CDMA and GSM.
CDMA mobile telephone systems are based on the technology which is used to operate central controllers. This technology is usually referred to as CDMA with a GSM prefix. In a typical CDMA system the central controller is programmed to retrieve a programmed sequence of data to be sent across the airwaves by the user, typically the local telephone company.
GSM cellular systems are often much less expensive to manufacture than CDMA because it uses a different technology. GSM cellular systems are often transmitted through wireless technology, which means the distance doesn’t need to be continuously measured, and so there is no need to have the same subscriber units to accommodate each subscriber. A GSM system can transmit over long distances quite effectively. So both types of mobile phone can be used, and both types have distinct advantages.