dual-SIM phones

With a Dual SIM phone, you can insert not one but two SIM cards at the same time. In many cases, you can be reached on both SIM cards, although there are exceptions. These types of phones are especially popular here among people who want to combine a personal and a work phone, but in other countries they’re also popular with people who are located near two coverage areas or who travel frequently and don’t want to keep switching SIM cards.

Differences Between Dual SIM Types

There are two types of Dual SIM: Standby and Active. With Dual SIM Standby (DSS), you must choose in advance which SIM card is active on the network; both cannot be active at the same time. You can switch or “shift” between SIM cards via a menu on your phone. This type is therefore sometimes also called “Dual SIM shift.”

A slightly newer technology is Dual SIM Dual Standby (DSDS). With this, both SIM cards are connected to the network, but you cannot use both at the same time. This is because there is only one antenna that is shared between both SIM cards. However, the antenna for data is different from the one for voice. This means you can make a call with one SIM card while using mobile data with the other at the same time. This type is the most common.

• Dual SIM Standby (DSS) – One SIM card registered and active
• Dual SIM Dual Standby (DSDS) – Two SIM cards registered, one active at a time
• Dual SIM Active (DSA) – Two SIM cards registered and active simultaneously

If you don’t want a call on one SIM card to go to voicemail while you’re making a call on the other, you’ll need Dual SIM Active (DSA), sometimes also called Dual SIM Dual Active (DSDA). These phones are equipped with two antennas, one for each SIM card. As a result, they are more expensive, use more battery power, and are less common.

Hybrid Dual SIM

And then there’s the Hybrid Dual SIM. With this type, the slot for the second SIM card is shared with the memory card slot. A drawback is that you’ll have to choose between inserting a second SIM card or a memory card—you can’t use both at the same time. This doesn’t necessarily have to be a problem for smartphones that come with plenty of built-in storage. If you’re considering a Dual SIM phone with this type of slot, make sure to choose one with sufficient built-in storage, because expanding it will come at the expense of your second SIM card.

Types of SIM Cards

Unfortunately, SIM cards come in various shapes and sizes. While they used to be as big as a credit card, these days they’re no bigger than a pinky fingernail. In terms of size, today’s options range from large to small: miniSIM (2FF), microSIM (3FF), and nanoSIM (4FF). Dual-SIM phones don’t always have to accept the same type of SIM; a combination of sizes is also possible. You can request a new SIM card in that size from your carrier. We do not recommend using a SIM card adapter to make a smaller SIM card fit into a larger slot. These often cause problems, such as damaging the contact points or simply getting stuck in the device. You also often lose your warranty coverage in the event of permanent damage.

eSIM

A relatively new type is the electronic SIM card, also known as an embedded SIM. This is permanently built into the device and cannot be replaced. Users can select their carrier via a menu and can also switch carriers more easily. We’ll be seeing this type much more often in the future, possibly combined with a physical SIM card slot. You can then insert a SIM card into the device, and combined with the built-in eSIM, you’ll have a dual-SIM phone at your disposal.