dual-SIM phones

With a Dual SIM phone, it is possible to insert not one but two SIM cards at the same time. In many cases, you can also be reached on both SIM cards, although there are exceptions. These types of phones are particularly popular here amongst people who want to combine a personal and a work phone, but in other countries they are also popular with people who are located near two coverage areas or who travel frequently and do not want to have to change SIM cards every time.

Differences between Dual SIM

There are two types of Dual SIM: Standby and Active. With Dual SIM Standby (DSS), you must choose in advance which SIM card is registered 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 referred to as ‘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, which is shared between both SIM cards. However, the antenna for data is different from the one for voice calls. This means you can make a call using one SIM card whilst using mobile data on the other at the same time. This is the most common type.

• 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, whilst making a call on one SIM card, you do not want a call on the other to go to voicemail, you will need Dual SIM Active (DSA), sometimes also referred to as Dual SIM Dual Active (DSDA). Such phones are fitted 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 is the Hybrid Dual SIM. With this type, the slot for the second SIM card is shared with that of the memory card. A drawback is that you’ll have to choose between inserting a second SIM card or a memory card; you can’t have both. In itself, this needn’t be a problem for mobile phones that have plenty of built-in storage. If you’re considering a Dual SIM phone with this type of slot, make sure you choose one with sufficient built-in storage, as 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. Whereas they used to be as big as a credit card, these days they’re no bigger than a little fingernail. In terms of size, the options today range from large to small: miniSIM (2FF), microSIM (3FF) and nanoSIM (4FF). Dual-SIM phones do not always have to accept the same type; a combination of types is also possible. You can request a new SIM card in that size from your mobile provider. 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’ll often find that your warranty is void 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. The user can select their provider via a menu and can also switch providers more easily. We’ll be seeing this type much more frequently 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.