Introduction to SIM:

SIM cards are small smart cards that fit inside cell phones based on the GSM technology. SIMs contains modified information about your friends and families as well as the network establishment and even phone book data. And you can put SIM card in another GSM phone very easily.

Purpose of SIM:

A SIM card is a digital ID chip in cell phones. The support and encoding capability of a SIM help to stop your cell phone from being stolen and your conversations from being any person. The SIM also stores personal data and billing information and can be interchanged between phones. So you can easily receive private calls even while using someone else's phone just by putting your single SIM in that cell phone.

Dual SIM:

Dual-SIM means that a mobile phone has two SIM sockets and the capability of using two SIM cards at the same time. A mobile phone with Dual-SIM can access two different phone numbers at the same time, whereas other SIM phones can only use one phone number.

Tri –SIM:

Tri-SIM means that a cell phone has three SIM sockets and the capacity of using tree SIM cards at the same time. A cell phone with three SIM can access three different phone numbers at the same time to receive calls and you can even dial as well.

CDMA:

CDMA is a radio technology invented by the Qualcomm Company. It enables large numbers of cell phones to work SIMultaneously in the same area by assigning each telephone a unique radio transmission pattern defined by a preset code. Verizon and Sprint are the two largest CDMA operators in the U.S.

Tri-SIM Problems:

The main problem which I have found out Is that if I am using double SIM mobile set and both SIM is active and working smoothly and if you use for voice call by SIM 1, and at that very moment SIM 2 automatically get switched off, it means if someone try to call you same time by SIM 2, caller will get the message that this no is currently switched off / user is busy / not reachable etc. and another problem is if someone tried to reached you by SIM 1 for a very urgent matter but you are busy with SIM 2 you will still not receive any waiting call alert which is particularly bad.

What are the main purposes of having tri-SIM cell phones?

Conclusion:

For readers I should only suggest you to not to buy tri-SIM cell phones, it is not giving you a greatest benefit for users. If you really want to use you can use double SIM but single SIM is always great for a real and sincere user.