In earlier days when mobile revolution was gaining grounds, the mobile phones or cell phones had limited functionalities and CDMA (the mobile communication method to transfer messages) based phones did not require SIM cards, but the technology advancements (e.g. GSM) have made it possible for new services and apps. Let’s see what these technologies are and their farthest possibilities.
GSM (Global System for Mobile Communications) based network uses SIM card, a SIM (Subscriber Identification Module) card, according to wisegeek.com and wiki’a, is a portable chip which holds personal information of a account holder (your account), including phone number, text massages and other information(unique serial number, international mobile subscriber identity, etc.). It can be removed from one handset and inserted into the other. CDMA (Channel Division Multiple Access) based cell phones do not use SIMs but store user’s data in the handsets itself.
SIMcard IN MOBILE
Each SIM card has a unique number printed on it, which is needed to be activated by the mobile phone service provider (or carrier). SIM cards only work with a particular service provider and the service plan that it offers. It can be activated by carrier’s website or by calling carrier directly. Pre-paid SIM cards allow flexibility of use without being tied to a particular carrier, you can switch to other local SIM cards in foreign country to save roaming charges.
A global SIM card works in multiple countries and requires a Global System for Mobile communication phone to work. There are services (SMS, voice mail, etc.) and availability of network that comes with a particular carrier and differ for one carrier to another. Global SIM cards require call phone that is capable of working in all countries; a quad-band phone works in majority of countries.Dual SIMs phones use two SIM cards and allow two different numbers to be communicated, usually, for professional and private callings or standby mode.
International SIM card, for travelers, from company to company, provides varying set of facilities, including free incoming SMS services, but not limited to data services, phone numbers and more.
Usually SIM cards are secured but new threat test has revealed that it is vulnerable to attacks, as mentioned by engadget.com/2013/07/22/sim-
card-hack, which means somebody can call up by using your SIM card. In
this case of security, you can use mobile security software to protect your
phone. Or you can use Calling Cards, which can be purchased online, and less complicated
According to wired.com/business/2010/01/ipad-mini-sim/, your phone’s SIM card does not work with iPad, which needs to be adjusted to fit it into iPad.
As more mobile communication technologies are developed, the new facilities might come into play.