你在商店里遇到过双卡智能手机吗？(Dual SIM)您想知道是什么让它们有用以及双 SIM 卡技术(Dual SIM technology)的工作原理吗？也许您已经知道这一点，但您仍然有一些疑问，例如双卡双待(Dual SIM Dual Standby)与双卡双活(Dual SIM Dual Active)有何不同？如果您想知道什么是双SIM 卡技术(SIM technology)，它是如何在现代智能手机中实现的，它的优点和缺点，请阅读这篇文章：
什么是双 SIM 卡？
任何手机或智能手机(phone or smartphone)都需要SIM（用户识别模块(Subscriber Identification Module)）卡才能连接到移动网络。可以同时容纳两张不同SIM卡的智能手机或手机(smartphone or phone)称为双 SIM 卡设备(Dual SIM device)。拥有两张SIM卡意味着双 SIM 卡智能手机(Dual SIM smartphone)可以使用两个SIM(SIMS)卡中的任何一个来拨打或接听电话。
换句话说，双 SIM 卡(Dual SIM)是某些智能手机的一项功能，允许它们同时持有和使用两张不同的SIM卡。
为什么双 SIM 卡(Dual SIM)智能手机有用？双卡(Dual SIM)的优势！
对于某些人来说，拥有双 SIM 卡智能手机(Dual SIM smartphone)可能会很有用。以商人和女性为例，他们往往有一个电话号码(phone number)用于工作，另一个号码用于朋友和家人。商务人士(business person)可以使用两种不同的智能手机，一种用于工作，另一种用于个人用途，或者使用双SIM 卡智能手机(Dual SIM smartphone)，两个电话号码(phone number)都处于活动状态。随身携带一部智能手机比携带两部智能手机更舒适。
您可能对双 SIM 卡智能手机(Dual SIM smartphone)感兴趣的另一种情况是，特别是如果您生活在新兴市场(emergent market)，您想使用一个电话号码(phone number)拨打电话，而另一个用于连接互联网。一些移动运营商有很好的语音计划，但数据计划昂贵，或者相反。在双 SIM 卡智能手机(Dual SIM smartphone)上，您可以结合来自两家不同运营商的两种不同计划，并在月底获得更便宜的账单。
另一个好处是，如果您的手机未锁定在特定网络中，您可以同时使用两个移动提供商，这意味着您可以获得更多的移动覆盖。如果您经常出国旅行，您可以在本国(home country)使用一张SIM 卡(SIM card)，另一张SIM 卡(SIM slot)用于您在前往的国家/地区购买的卡，以获得更好或更便宜的覆盖范围。
如果您的Android 智能手机(Android smartphone)是双SIM 卡(SIM)并且您想了解如何配置它，请按照本指南中显示的步骤操作：如何使用Android设置(Android)双 SIM 卡智能手机(Dual SIM smartphone)（用于通话、短信(SMS)、数据等的默认SIM 卡）。(SIM)
双 SIM 卡(Dual SIM work)如何工作？有哪些类型的双 SIM 卡(Dual SIM)模式？
如果您决定购买双 SIM 卡智能手机(Dual SIM smartphone)，您应该知道有几种不同的双 SIM 卡(Dual SIM)实现方式，其中一些比其他的更好。以下是可用的双 SIM 卡(Dual SIM)实施类型：
- Dual SIM Single Standby (Passive) - 这是Dual SIM 技术(Dual SIM technology)最糟糕的实现方式，价格适中的手机通常使用它。双卡无源(Dual SIM Passive)手机可以使用两张不同的SIM 卡(SIM card)，但任何时候只能使用其中一张。这意味着当一张SIM 卡(SIM card)工作时，另一张就无法访问。要使用第二张SIM 卡(SIM card)，您需要手动激活它，当您这样做时，第一张SIM 卡会停用。(SIM)您在智能手机中找不到这种实现，只是在较旧的手机中。
- Dual SIM Dual Active - 此实现允许您从智能手机内的两张SIM卡拨打电话。它还可以同时接听两张SIM卡中的任何一张的电话。Dual SIM Dual Active智能手机的两个SIM卡都永久有效，当您在其中一个上进行对话时，另一个仍然可以工作并接听电话、消息或数据。例如，如果您在第一个 SIM 卡上打了一个电话，而您在第二个(SIM)SIM 卡(SIM)上接到另一个电话，您会收到通知。Dual SIM Dual Active手机的缺点是这些设备有两个无线电收发器，每个无线电收发器一个SIM 卡(SIM card)。这意味着它们比普通的单 SIM 卡(Single SIM)智能手机消耗更多的电池，并且制造成本更高，从而导致价格更高。这也是为什么很难找到具有这种实施方式的智能手机的原因。
- Dual SIM Dual Standby - 它是Dual SIM Standby和Dual SIM Dual Active的混合体。Dual SIM Dual Standby让您的智能手机拥有两张有效的SIM卡，并且它们都只使用一个无线电收发器(radio transceiver)。但是，它们只有在您不使用它们时才处于活动状态，因此称为Dual Standby。只要SIM卡都处于待机(Standby)模式，您就可以在其中任何一个上拨打和接听电话。但是，一旦您在一张SIM 卡(SIM card)上接听电话，另一张 SIM 卡将变为非活动状态，直到不再使用第一张卡。如果移动网络中的一个或两个都是如此(mobile network)如果您已连接，请使用 2G 进行电话通话。如果您的移动网络(mobile network)是 3G 或 4G，并且不使用 2G 进行语音通话，则不存在此限制。这并不理想，但该技术在现代智能手机中更便宜且更普遍。双待(Dual standby)手机只需要额外的空间再放一张 SIM 卡(SIM card)。因此，与单SIM 卡版本(SIM version)相比，成本增加(cost increase)是微不足道的。
为了让您更容易理解不同类型的双 SIM 卡(Dual SIM)实现之间的差异，我们创建了这个简单的比较表(comparison table)：
使用双卡智能手机时，您可以在两张(SIM smartphone)SIM卡上使用您的 3G/4G 数据计划吗？
简短的回答是Yes，但这取决于您的智能手机制造商选择的双 SIM 卡实施(Dual SIM implementation)。制造商关注他们的智能手机的制造成本和利润率。使用支持 4G 数据连接和另一个 2G 数据连接的SIM 卡(SIM card)制作双SIM 卡智能手机既简单又实惠。(SIM smartphone)4G + 2G 可以组合成双卡双待(Dual SIM Dual Standby)模式并使用相同的无线电频率。但是，如果您想在其中一个 SIM 上构建支持 4G 连接的双 SIM 卡智能(Dual SIM smartphone)手机(SIM)卡和3G甚至4G，这意味着智能手机上的处理器必须足够强大才能同时支持两个高速数据连接，并且成本可能会相当高。市场上大多数双 SIM 卡智能手机(Dual SIM smartphone)都提供 4G + 2G 数据连接。
双卡(Dual SIM)智能手机的缺点
这项技术并不完美，一些缺点值得考虑：
- Dual SIM Dual Active智能手机的待机自主性较短，因为它们有两个无线电收发器，而不是一个。
- Dual SIM Dual Standby通常将microSD 插槽(microSD slot)用于第二个SIM。因此(Therefore)，在大多数情况下，如果您使用两张SIM卡，则无法使用一张microSD 卡(microSD card)来扩展您的存储空间(storage space)。如果您需要双 SIM 卡智能手机(Dual SIM smartphone)，您应该花更多的钱购买具有更多内置存储空间(storage space)的版本，这样您就不需要microSD 卡(microSD card)。
- 在大多数情况下，智能手机制造商使用 4G + 2G双卡双待(Dual SIM Dual Standby)实现，这意味着一张SIM 卡(SIM)只能用于通话和短信，不能用于数据连接。它限制了双卡(Dual SIM)智能手机的实用性。
双卡智能手机示例
由于成本和提供的功能之间的平衡，市场上大多数双卡双待智能手机都是双(SIM)卡双待(Dual SIM Dual Standby)智能手机。如果您想购买这样的设备，这里有一些不错的选择：华为 P20 Pro(Huawei P20 Pro)、华为 Mate 20 (Huawei Mate 20) Pro、三星 Galaxy Note 9(Samsung Galaxy Note 9)、三星 Galaxy S8(Samsung Galaxy S8)、LG G6、一加 6T、小米米 8(Xiaomi Mi 8)、华硕 Zenfone (Asus Zenfone )5Z、诺基亚 6.1(Nokia 6.1)和摩托罗拉 Moto G5。
iPhone 上的双 SIM 卡怎么样？
苹果(Apple)传统上拒绝在其 iPhone 上使用双 SIM 卡的想法。(Dual SIM)但是，iPhone XS、iPhone XS Max和iPhone XR是第一款提供此类支持的Apple智能手机。(Apple)这三款 iPhone 型号可以使用可拆卸 nano - SIM和不可拆卸 e SIM。e SIM是一种数字SIM 卡(SIM card)，可让您从运营商处激活移动计划，而无需为此使用物理SIM。
Apple 使用双卡双待(Dual SIM Dual Standby)( DSDS ) 技术，因此 nano-SIM 和 eSIM 都可以拨打和接听电话。但是，尽管该实施允许您同时使用两个不同的手机号码，但它仅适用于运营商支持 eSIM 的某些国家/地区。不幸的是，目前该列表相当短 - 24 个国家/地区，您可以在此Apple 网页(Apple web)上看到：查找提供 eSIM 服务的无线运营商(Find wireless carriers that offer eSIM service)。
你喜欢双卡智能手机吗？
双 SIM 卡(Dual SIM)智能手机在某些情况下很有用，智能手机制造商已经开始注意到人们想要这样的设备。因此，每年都会出现越来越多的双 SIM 卡。(Dual SIM)但是，正如您在本文中看到的那样，并非所有双 SIM 卡(Dual SIM)设备的工作方式都相同，并且某些双 SIM 卡(Dual SIM)实现比其他设备更好。请在下面的评论中告诉我们您对这项技术的体验以及您对此的看法。
Dual SIM - What is it? What does Dual SIM mean? How does Dual SIM work?
Have yоu encountered Dual SIM smartрhones in shops? Do you want tо know what makes them useful and how the Dual SIM technоlogy works? Maybe yoυ already knоw that, but you still have questions like what makes Dual SIM Dual Standby different from Dual SIM Dual Active? If you want to know what the Dual SIM technology is, how it is implemented in modern day smartphones, its advantages and disadvantages, read this article:
What is Dual SIM?
Any mobile phone or smartphone requires a SIM (Subscriber Identification Module) card to connect to the mobile network. A smartphone or phone that can hold two different SIM cards at the same time is called a Dual SIM device. Having two SIM cards means that a Dual SIM smartphone can use either of the two SIMS to initiate or to receive phone calls.
In other words, Dual SIM is a feature of some smartphones that allows them to hold and use two different SIM cards, simultaneously.
Why are Dual SIM smartphones useful? The advantages of Dual SIM!
For some people, having a Dual SIM smartphone can be useful. Take, for instance, businessmen and women who tend to have one phone number for their work and another number for their friends and family. A business person can either use two different smartphones, one for work and one for personal use, or use a Dual SIM smartphone, with both phone numbers active on it. Having one smartphone to carry around is more comfortable than carrying two smartphones.
Another situation in which you might be interested in a Dual SIM smartphone, especially if you live in an emergent market, is when you want to use one phone number for phone calls, and the other for connecting to the internet. Some mobile operators have good voice plans, but pricey data plans, or the other way around. On a Dual SIM smartphone, you can combine two different plans from two different operators and get a cheaper bill at the end of the month.
Another benefit is that you can use two mobile providers simultaneously if your phone is not locked into a specific network, which means that you can get more mobile coverage. If you travel a lot abroad, you can use one SIM card in your home country and the other SIM slot for cards you purchase in the countries you travel to, for better or cheaper coverage.
If your Android smartphone is Dual SIM and you want to learn how to configure it, follow the steps shown in this guide: How to set a Dual SIM smartphone with Android (default SIM for calls, SMS, data, etc).
How does Dual SIM work? What types of Dual SIM modes are there?
If you decide to purchase a Dual SIM smartphone, you should know that there are several types of Dual SIM implementations that work differently, and some are better than others. These are the types of Dual SIM implementations available:
- Dual SIM Single Standby (Passive) - this is the worst implementation of the Dual SIM technology, and affordable phones commonly use it. A Dual SIM Passive phone is capable of using two different SIM cards, but only one of them can be active at any time. That means that when one SIM card works, the other is unreachable. To use the second SIM card, you need to activate it manually, and the first SIM deactivates when you do that. You do not find this implementation in smartphones, just older mobile phones.
- Dual SIM Dual Active - this implementation allows you to make phone calls from both of the SIM cards inside your smartphone. It can also receive calls on either of the two SIM cards, at the same time. Dual SIM Dual Active smartphones have both their SIM cards permanently active and, when you are having a conversation on one of them, the other still works and receives calls, messages or data. For instance, if you have a call on the first SIM and you are getting another call on the second SIM, you are notified about it. The disadvantage of Dual SIM Dual Active phones is that these devices have two radio transceivers, one for each SIM card. It means that they consume more battery than regular Single SIM smartphones and they are more expensive to manufacture, leading to a higher price. It is also the reason why it is challenging to find smartphones with this implementation.
- Dual SIM Dual Standby - it is a hybrid between Dual SIM Standby and Dual SIM Dual Active. Dual SIM Dual Standby lets your smartphone have two active SIM cards, and they both use only one radio transceiver. However, they are both active only as long as you are not using them, hence the name of Dual Standby. As long as the SIM cards are both in Standby mode, you can make and receive calls on any of them. However, once you take a call on one SIM card, the other becomes inactive until the first card is no longer actively used. That is true if one or both of the mobile networks you are connected to, use 2G for phone calls. If your mobile network(s) are 3G or 4G and do not use 2G for voice calls, this limitation does not exist. This is not ideal, but the technology is less expensive and more widespread in modern smartphones. Dual standby phones only require additional space for one more SIM card. So, the cost increase compared to the single SIM version is marginal.
To make it easier for you to understand the differences between the different kinds of Dual SIM implementations, we created this simple comparison table:
Can you use your 3G/4G data plan on both SIM cards, when using a Dual SIM smartphone?
The short answer is Yes, but it depends on the Dual SIM implementation that was chosen by the manufacturer of your smartphone. Manufacturers look at how much their smartphones cost to build and their profit margins. Making a Dual SIM smartphone with a SIM card that supports 4G data connections and the other 2G, is easy and affordable. 4G + 2G can be combined in a Dual SIM Dual Standby mode and use the same radio frequencies. However, if you want to build a Dual SIM smartphone that supports 4G connections on one of its SIM cards and 3G or even 4G on the other, that would mean that the processor on the smartphone must be powerful enough to support two high-speed data connections simultaneously and probably the costs would be rather high. Most Dual SIM smartphones on the market offer 4G + 2G data connections.
The disadvantages of Dual SIM smartphones
This technology is not perfect, and some disadvantages are worth considering:
- Dual SIM Dual Active smartphones have a shorter standby autonomy because they have two radio transceivers, instead of one.
- Dual SIM Dual Standby usually uses the microSD slot for the second SIM. Therefore, in most cases, you cannot use a microSD card to extend your storage space, if you use two SIM cards. If you need a Dual SIM smartphone, you should spend extra for a version that has more built-in storage space, so that you do not need a microSD card.
- In most cases, smartphone manufacturers use a 4G + 2G Dual SIM Dual Standby implementation, meaning that one SIM can be used only for calls and text messages, not for data connections. It limits the usefulness of Dual SIM smartphones.
Examples of Dual SIM smartphones
Because of the balance between their cost and the features they offer, most Dual SIM smartphones available on the market are Dual SIM Dual Standby smartphones. If you want to buy such a device, here is a list with some good options: Huawei P20 Pro, Huawei Mate 20 Pro, Samsung Galaxy Note 9, Samsung Galaxy S8, LG G6, OnePlus 6T, Xiaomi Mi 8, Asus Zenfone 5Z, Nokia 6.1 and Motorola Moto G5.
What about Dual SIM on iPhones?
Apple has traditionally rejected the idea of Dual SIM on its iPhones. However, the iPhone XS, the iPhone XS Max, and the iPhone XR are the first Apple smartphones that offer such support. These three iPhone models can use a removable nano-SIM and a non-removable eSIM. The eSIM is a digital SIM card that lets you activate a mobile plan from a carrier, without having to use a physical SIM for that.
Apple uses a Dual SIM Dual Standby (DSDS) technology, so both the nano-SIM and the eSIM can make and receive calls. However, although the implementation lets you use two different mobile phone numbers simultaneously, it only works in some countries where carriers offer support for eSIMs. Unfortunately, the list is rather short at the moment - 24 countries, which you can see on this Apple web page: Find wireless carriers that offer eSIM service.
Do you prefer Dual SIM smartphones?
Dual SIM smartphones can be useful in some instances, and smartphone manufacturers have started to notice that people want such devices. As such, more and more Dual SIMs appear each year. However, as you have seen in this article, not all Dual SIM devices work the same, and some Dual SIM implementations are better than others. Let us know about your experience with this technology and what you think about it, in the comments below.
