Dual SIM is an interesting feature for the user or professional who needs to use it two different mobile phone numbers on one device. Instead of buying, maintaining and transporting two terminals, using two SIM cards allows the same functionality with the convenience and savings of managing a single smartphone.

SIM cards (Subscriber identification module) are mandatory for access to the most widely used GSM mobile networks and are supplied by providers when we contract one of their services. They use a lightweight operating system customized by the manufacturers themselves or based on Java, and their main purpose is to store specific network information used to authenticate and identify subscribers. They also have some other functions, such as a list of contacts or numbers, and the most advanced ones support near field technology, NFC.

These removable cards can be removed and inserted from the mobile phone (they are removable) and are available up to four sizesfrom the largest original SIM to the rest of the available formats, mini, micro and nano, the smallest.

In the short term, they will be replaced by new eSIMs, virtual SIM cards of the next generation, which have much more potential and relevant advantages, including easier access to the dual SIM functions we are discussing, since they will be able to use more phone numbers. and services and from several operators. Nowadays, there are many mobile phones that combine physical SIM and eSIM and achieve the same functions.

Dual SIM, uses and types

The ability to use two different phone numbers on one terminal is the most transparent type of use for two SIM cards. Another advantage is that you can use two mobile operators at the same time, if the phone is not locked to a specific network and thus achieve greater mobile coverage.

Another example of use can be found in some markets, especially emerging markets, to separate voice and data rates. In some regions, there are mobile operators that offer good deals for voice but not for data, or vice versa. In this context and with dual SIM you can lower your total monthly rate.

If you are traveling abroad and are still being charged roamingusing a SIM card in your home country and using a second slot for a SIM card purchased specifically in the country you are traveling to will provide coverage benefits and/or better pricing.

No two SIM cards are the same as there are different implementations that you need to know. Basically these three:

– Two SIM cards, one standby (passive). This is the worst-case scenario for the application of this technology, although it is no longer used in modern smartphones. Dual Passive SIM is able to use two different SIM cards, but only one of them can be active at any given time. To use the second SIM card, it must be activated manually, and the first one is deactivated in this case.

– Dual SIM Dual Active. Two SIM cards are permanently active, so you can make and receive phone calls, messages or use data from both cards interchangeably. If you make a call with the first and receive another call with the second, you will receive a notification about it. The disadvantage of this type is that they have two radio transceivers, one for each SIM card. They use more battery and are more expensive, so they are usually hard to find.

– Dual SIM Dual Standby. It is a hybrid of the previous ones. It has two active SIM cards, but both use the same radio transceiver. You can make and receive calls on either of them, but once you activate one, the other becomes inactive. This restriction only applies to 2G networks, not 3G and 4G networks. This is the most common type and the one commonly found in a modern consumer smartphone. The technology is cheaper and the consumption is lower than the previous one.

The use of dual SIM has some limitations and disadvantages. Dual card support requires more powerful processors, so not all offer a 4G+4G scenario and tend to use 4G for data and 2G/3G for voice implementations. There are also limitations with 5G and on some phones if you want dual SIM you won’t have access to 5G. It happened back then with the iPhone 12 due to compatibility issues with the Qualcomm modem.

Another aspect to consider is that the second Dual SIM Dual Standby card generally uses the same slot as the microSD, and in some mobile phones these cards are necessary to increase the storage capacity. Not all, because there are models with dual SIM and an additional microSD.

Availability of mobile phones with dual SIM

Chinese manufacturers that work with Android are the ones that offer the most deals and in smartphones of all price ranges and features. Some models are made directly with two SIM cards, while others are specific variants of general models. It is simply a matter of checking its specifications as there are many to choose from.

For users who prefer iOS there is also a menu. Although Apple has traditionally rejected this feature, the iPhone XS, XS Max and

If you are looking for this type of configuration, please read the terminal specifications and implementation type first, as they may vary. That means dual SIM is still there very useful in some scenarios.