Difference Between Dual SIM and Dual Standby SIM

Dual SIM vs Dual Standby SIM
 

Difference between Dual SIM and Dual Standby SIM can be very easily explained. Dual SIM means that a device, for instance, a phone can hold two SIMs. There are various sub-types of Dual SIM such as Dual SIM Switch, Dual Standby SIM, and Dual Active SIM. So it is important to note that Dual Standby SIM is a type of dual SIM technologies and the term Dual SIM is a common term to mean any of those Dual SIM methods. So, when a phone manufacturer says Dual SIM, it can be any of the dual SIM methods. Hence, we have to dig more into the specification to see what the real method is. Dual SIM Switch enables only one SIM to be used where, by using a menu switch, the active SIM is selected. In Dual Standby SIM, both SIMs are active during standby, but cannot be actively used at the same time. That is you can receive/send messages or calls using both SIMS but, when one SIM is busy being used for a call or some other purpose, other SIM cannot be used.

What does Dual SIM mean?

Dual SIM refers to a situation on a device, such as a phone, where it can hold two SIMs. Dual SIM phones would have two separate SIM slots where each can hold one SIM. Even certain single SIM phones that have just one SIM slot can be made dual SIM by using an adaptor. Dual SIM divides into to various types depending on how the SIMs are made active. First type is called “Dual SIM Switch” where the phone supports two SIMs but only one is active at a time. The active SIM must be selected when restarting the phone or from a menu. While one is active, the other SIM is totally inactive as if it was removed. This is the most basic and lowest cost method, and hence, it is very much used in low-cost dual SIM phones. When an adaptor is used to make a single SIM phone dual SIM as well, the mode of operation would be “dual SIM switch”. The second type of Dual SIM is “Dual SIM Standby“. Here both SIMs are active at the same time that any SIM can receive/make calls, send/receive messages. But, when one SIM is busy, for instance during a call, the other SIM will be inactive. The third type is Dual SIM Active where both SIMs are active and usable simultaneously. This is achieved by including two radio units in the phone one unit per each SIM. So in this case even when one SIM is making a call, if a call is received to the other SIM still it will be notified real-time. So, in this case, both SIMs are really active and it is just like you are using two separate phones for each SIM. But, two radio units come with increased cost and higher power consumption.

Difference Between Dual SIM and Dual Standby SIM

What does Dual Standby SIM mean?

As explained earlier, this is one of the dual SIM operation methods. Here, when under standby, both SIMs are active. That is, you would receive calls or messages from any SIM or you can make a call or send message from any SIM. But, when calling, you can select the SIM that you would like to use to make the call. When sending a message as well, you can similarly select. When receiving call and messages, no matter to what SIM the message or call comes, you will receive it. But the limitation is that, while one SIM is busy; that is, for example, when one SIM is used to make or receive a call, other SIM will be deactivated. For example, say first SIM is being used for a call, now you will not receive any messages or calls onto the second SIM until the call on the first SIM ends. As a summary, both SIMs are in the standby mode but cannot be actively used at the same time. This is the currently most used method in Dual SIM phones. Most moderate to high-cost phones that are advertised dual SIM uses this “Dual standby SIM” method. To implement dual standby SIM method, only one radio unit is necessary. Both SIMs use the radio unit by sharing the time through time division multiplexing. When one SIM exclusively use the radio unit; for example, when making a call, the other SIM won’t get the chance to use the radio unit and hence will be deactivated.

What is the difference between Dual SIM and Dual Standby SIM?

• Dual SIM means that a device can hold two SIMS.

• There are various methods of Dual SIM where the term Dual SIM is an umbrella term that refers to all these sub-types of dual SIM methods.

• Dual Standby SIM is a type of Dual SIM, where a single radio unit on the device is used to keep both SIMs on standby using a technology called time division multiplexing.

Summary:

Dual SIM vs Dual Standby SIM

Dual SIM refers to a situation that a device like a phone can hold two SIMs. Dual SIM is a common term that refers to all types of Dual SIM operation methods such as Dual Sim Switch, Dual Standby SIM and Dual Active SIM. Dual Standby SIM, hence, is a subtype of Dual SIM methods. In Dual Standby SIM method, both SIMs can be used under standby mode. That is both can receive/make call or messages. But, when one SIM is actively used for a call for example, the other SIM would be deactivated until the call ends.

 

Images Courtesy:

  1. Dual SIM phone by Ilya Plekhanov (CC BY-SA 3.0)