Apple iPhone Dual SIM Dual Standby - what it does and how eSIM technology works

Dual SIM Dual Standby and eSIM are both relatively recent additions to Apple's mobile device lineup. Here's what they are and what they mean to iPhone and Apple Watch users.


Modern mobile devices are getting smaller, faster, and smarter, allowing their users to better connect and interact with the world around them. The adoption of new mobile technologies has been growing at a rapid pace, meaning users hearing about new Apple devices like the new iPhone Xs or the Apple Watch Series 4 may not have heard of fancy terms like DSDS or eSIM. Fortunately, we're here to clear the air on exactly what Dual SIM Dual Standby and eSIM technologies do, as well as what they mean for mobile users.

What is Dual SIM Dual Standby?

Dual Sim Dual Standby, also known as DSDS, is the modern take on Dual SIM functionality. Traditionally, Dual SIM means users can install two separate SIM cards into their phones — more on that later — while Dual SIM Standby typically allows the user to choose which of those two SIMs are able to place and receive calls. On the other hand, Dual Sim Active (or DSA) technology allows both SIMs to receive calls simultaneously, though the device itself would need two transceivers. Dual SIM Dual Standby combines the best of all these functions together, allowing users to put two active SIMs into their phones while utilizing just one transceiver.

Why would anyone need dual SIM functionality?

There are two main reasons why mobile users would want a Dual SIM-compatible phone: the first is that they want to use the same device for two different numbers, while the second is that they may want to use their device with two different carrier plans.

The first example is fairly self-explanatory: typically the user wants to have his or her personal and work numbers go to the same device. This means they can give work numbers to work associates, personal numbers to personal friends, and manage both numbers through the same phone. It's similar to how e-mail users can have multiple accounts forwarded to a single main account, allowing them to manage all of their communication without needing separate devices or separate logins.

The second example is also straightforward: by having two SIM slots, a single device can work with multiple carriers and networks, which is a great feature for those who travel often. With a Dual SIM compatible device like the iPhone Xs, a mobile user can keep their usual stay-at-home mobile plan but also pick up a new plan for when they travel abroad. Instead of paying crazy roaming fees while out of the country, the device owner could simply pick up a carrier plan within the country or continent they're visiting, slot the new SIM card into their phone, and have all the comfort and familiarity of their mobile device while operating on a completely different cellular network.

What is eSIM and how does it work?

The term "eSIM" is an amalgamation of the words "electronic" and "SIM," simply referring to an electronic, non-replaceable variant of a traditional SIM card. In a nutshell, it's the functionality of a SIM card without the card itself — there's no physical card, nor is there a tray or slot in which to place one. Instead, the SIM exists electronically, with data and values that can be written or rewritten by the host device.

eSIM is considered the new modern standard for mobile devices, with more and more phones supporting eSIM functionality as time moves forward. Users with new phones will still have to call a number or undergo similar procedures to activate their devices, but they won't need any sort of physical interaction with regards to the card, which also removes the need for additional slots or removable plates on the device.

Since eSIM technology allows devices to save on precious interior space, it's a clear choice for slimmed-down devices like the iPhone Xs or the new Apple Watch Series 4.

Modojo @ Shacknews is your source for all mobile- and portable-oriented news and guides. Keep it tuned here to Shacknews for all the latest coverage, and be sure to stop by our Apple home page to learn all of the latest developments with regard to the iPhone Xs, iPhone Xr, and Apple Watch Series 4.

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