What is Dual SIM ?

 This specifies whether a device is capable of supporting two SIM cards. The two major types of dual-SIM phones are active and standby. Dual-SIM Standby (DSS) requires the user to specify which of the two SIMs is able to make and receive calls, while Dual-SIM Active (DSA) enables both cards to receive calls at the same time. This latter feature usually requires an additional transceiver for the secondary SIM card, and as such consumes more battery life. More recent models feature Dual SIM Dual Standby (DSDS) technology which enables them to have two active SIMs with only one transceiver.

What is Dual SIM ?

Any mobile phone or smartphone requires a SIM (Subscriber Identification Module) card to connect to the mobile network. A smartphone or phone that can hold two different SIM cards at the same time is called a Dual SIM device. Having two SIM cards means that a Dual SIM smartphone can use either of the two SIMS to initiate or to receive phone calls . In other words, Dual SIM is a feature of some smartphones that allows them to hold and use two different SIM cards, simultaneously.

Types of Dual SIM Model:-

 These are the types of Dual SIM implementations available:

• Dual SIM Single Standby (Passive) – this is the worst implementation of the Dual SIM technology, and affordable phones commonly use it. A Dual SIM Passive phone is capable of using two different SIM cards, but only one of them can be active at any time. That means that when one SIM card works, the other is unreachable. To use the second SIM card, you need to activate it manually, and the first SIM deactivates when you do that.

• Dual SIM Dual Active – this implementation allows you to make phone calls from both of the SIM cards inside your smartphone. It can also receive calls on either of the two SIM cards, at the same time. Dual SIM Dual Active smartphones have both their SIM cards permanently active and, when you are having a conversation on one of them, the other still works and receives calls, messages or data.

• Dual SIM Dual Standby – it is a hybrid between Dual SIM Standby and Dual SIM Dual Active. Dual SIM Dual Standby lets your smartphone have two active SIM cards, and they both use only one radio transceiver. However, they are both active only as long as you are not using them, hence the name of Dual Standby. As long as the SIM cards are both in Standby mode, you can make and receive calls on any of them. However, once you take a call on one SIM card, the other becomes inactive until the first card is no longer actively used.