I have used SIM cards and so have so many people. I do not understand the underlying mechanism or technology behind SIM cards so this is the right opportunity for me to ask someone with expert knowledge of SIM card. Please help me to understand how this simple SIM card works. I want to know how it is manufactured, which materials are used to manufacture it, and how data is transferred from the phone to the SIM card and vice versa.
SIM card and the Intricate Inner Working with Phones
Hi, George!
 Very interesting question. A SIM (subscriber identification module) circuit is embedded into a removable plastic card. Its size follows the classic standards. All sim cards allow maximum of 250 contacts entered or stored. As for the way it works and transfers data, there is a very big and detailed article on Wikipedia, as its complex to answer in few lines, I recommend you to read and learn everything about them – Subscriber identity module
Regards,
Mathew Tand
SIM card and the Intricate Inner Working with Phones
The term SIM refers to Subscriber Identity Module. A SIM card is a portable memory chip that is mostly used on mobile phones, Smartphones, and other smart devices that requires cellular network connectivity. It normally operates on GSM network or Global System for Mobile Communications. It contains the personal information of the account holder like the phone number, text messages, address book, subscribed services and features, and other data.
When a user decides to change a handset, the SIM card can easily be removed from the handset and transfer it to the new handset. Normally, after a SIM card has been manufactured, it has a specific time frame or period when unused and after that it will expire. Once you insert a newly bought SIM card into your phone and you start your handset, the SIM card is automatically activated.
In the old days, all mobile phones use the same size of SIM cards. But nowadays, when Smartphones started appearing, SIM cards are now being sold in different sizes. There are Smartphones that use a micro-SIM card and here, a regular SIM card will not fit.
