Two SIM cards in a modern smartphone are perhaps the standard that even eminent market leaders such as Samsung do not neglect. Even the conservative Apple has similar developments. Often, such devices are confused with phones equipped with two radio modules, in fact, we are not talking about ordinary phones with two SIM cards. Two radio modules are an opportunity to use each of them at a time. Most devices, unfortunately, only allow each SIM card to be used interchangeably while the second is in standby mode.
Technology: DSDS and DSDA
Almost all, without exception, phones currently on the market work with two SIM-cards in DSDS (Dual SIM - Dual Standby) mode, which implies the alternate work of each of them. Both SIM-cards adopted in the gadget use one radio module for communication, which means that making a call using one of them, it will be impossible to receive a call to the other. The same applies to the Internet, talking on the phone using one SIM card, it will be impossible to use mobile Internet on another.
In the case of DSDA (Dual SIM - Dual Active) the situation is exactly the opposite, cell phones with two radio modules are able to interact with each SIM card in parallel, without interrupting each other's work.
Phones with two radio modules: pros and cons
Of course, such devices are not acquired out of idle interest, they have a number of advantages that attract attention:
- A phone with two active radio modules allows its owner to never lose touch. Where the SIM card of one operator may be powerless, the card of the other will do just fine, therefore the presence of two simultaneously functioning radio modules favorably affects the availability of the user as a subscriber.
- Another advantage of such gadgets is a more stable operation of the mobile Internet, which does not turn off even if you talk on one of the SIM cards.
- Naturally, mobility. Two SIM-cards, coupled with two radio modules forever eliminate the need to have and carry two phones.
- Last on the list, but far from the last by value plus - the ability to combine the favorable conditions of two different operators. There can be a great many schemes, because each operator has its own conditions. In addition, many people love to travel and certainly will not do without an additional SIM card in addition to the main one.
The rainbow picture described above is spoiled by several drawbacks:
- Firstly, phones with two radio modules require high expenses in production, components come out more expensive, the assembly and optimization process is much more complicated.
- Secondly, the radio module is a complex device and at the same time the most demanding in the phone (after the display). Both facts lead to inevitable losses in autonomy, forcing them to constantly live near a power outlet or carry a portable battery with them.
- Thirdly, there are studies claiming that radio waves adversely affect the human body, leading to the development of cancer. The presence of two radio modules in the phone is the same as holding two phones near the head at a time. Many believe that in this way you can literally fry the brain.
Fall offer
Obviously, the number of phones supporting DSDA is incomparably small, compared to phones that do not support this technology. It is believed that such devices were banned in the European Union due to the excessive radiation of such smartphones that do not meet the standards of countries within the union. There is a certain theory of a conspiracy of operators, allegedly they do not want to see a competitor's SIM card in the same phone next door. One way or another, the market cannot boast a rich assortment of DSDA smartphones, but you can still find a couple of diamonds.
HTC Desire 700
Taiwanese office of HTC, perhaps the most distressed smartphone market. The once thriving brand, over the past 5 years has lost everything: money, fame, reputation. Nevertheless, HTC continues to release devices, has its own unique, and most importantly recognizable style.
Desire is a symbiosis of style and build level of high class, with the "hardware" of the budget class. The price of all this stuff varies within the average.
On the front panel of the Desire 700 is a large 5-inch display with a resolution of 960 by 540 (dots per inch - 220). The heart of the smartphone is a Spreadtrum Shark chip with a clock frequency of 1200 megahertz, atypical for the manufacturer. Also, under the hood of the smartphone, 1 gigabyte of RAM and 8 gigabytes of main memory were covered (there is support for memory cards up to 64 gigabytes). The battery size is not impressive either, with a rather impressive size, only 2100 milliamp hours of battery could fit into the gadget.
Supported network standards: GSM and HSDPA
HTC One M7 Dual
Another gadget about a Taiwanese manufacturer, this time a flagship. The M7 model was released not so long ago, therefore it is more than relevant and advanced.
On the front of the M7 took its place quite a large 4.7-inch display with a high resolution of 1920 by 1080 pixels (dots - 469), with Super LCD technology. For performance meets the popular processor from Qualcomm, clocked at 1,700 megahertz. The memory capacity is twice that of the Desire 700: 2 gigabytes of RAM and 32 gigabytes of ROM. Inside installed battery for 2300 milliamp hours.
Boom Sound speakers, which allow you to play high-quality stereo sound directly through the speakers of your smartphone, have become the branded “feature” of the device. Also a distinctive feature is a 4-megapixel camera with double pixel technology for high-quality shooting in the dark.
Supported network standards: GSM and WCDMA
Given the fact that mobile phones with two radio modules have become outlandish, a similar solution from HTC looks extremely worthy and attractive.
Huawei Honor 7
The manufacturer of smartphones from China, with an unpronounceable name, has recently begun expansion into the Russian market and the market of the CIS countries. The brand is actively promoting itself on the Internet, popularized by mobile operators, and all this is eloquent by CEOs who promise to sweep away all competitors in the coming years. Among other things, Huawei loves phones with two radio modules, the list of which in the company's assortment is quite extensive.
One of the best gadgets, smoothly balancing between price and quality - Huawei Honor 7, released in the middle of last year. The phone has a large display with a diagonal of 5.2 inches and a resolution of 1920 by 1080 pixels. Behind it lies the power of the proprietary Silicon Kirin 935 chip with a frequency of up to 2200 megahertz. The volume of memory, which the Chinese never skimp on, 3 gigabytes of RAM and up to 64 core, is also pleasing. Another argument in favor of Honor 7 is a large battery with a capacity of 3100 milliamps hours.
As for the supported communication standards, the situation here is very ambiguous, since each model has a unique set of radio modules designed for a specific market.
ASUS ZenFone 2
The leader of this list is definitely the best phone with two radio modules on Android. ASUS product may not look like a flagship, but it is able to hook on its internal beauty, a powerful technical component.
ZenFone 2 has the largest display in the collection, a giant, saturated, 5.5-inch capacitive screen with a resolution of 1920 by 1080 pixels, protected by a third-generation Gorilla Glass coating. High-performance smartphone provides a processor from Intel, which has a 64-bit architecture and 4 cores, each of which has a clock frequency of 1800 megahertz. The amount of RAM in 4 gigabytes allows you to actively use many, one-time running applications, without the threat of unloading them from memory and data loss. 32 gigabytes of main memory can be supplemented with another 64 gigabytes, a microSD card. For a long time, a single charge supports a 3000 mAh battery. Two cameras complement the picture: the rear one at 13 megapixels and the front one at 5.
Supported network standards: GSM and HSDPA
Zopo ZP980
An option for those who prefer a simpler device. The Chinese brand Zopo is more like some kind of fake, but nevertheless deserves attention, since it has two radio modules.
The first thing that catches your eye is the impressive display diagonal (5 inches) and resolution (1920 by 1080 pixels). At the same time, the device retains a fairly compact size. Unfortunately, this is all that can impress in this budget Chinese. The device has a chip from MediaTek with a clock frequency of 1200 megahertz, a small amount of RAM, only 1 gigabyte. The amount of internal memory is also not impressive, 16 gigabytes with the ability to expand due to memory cards. The device turned out to be thin, therefore there was no place for a large battery, the owners of the gadget will inevitably have to put up with a battery, the volume of which is 1860 milliamps hours.
In general, the Zopo ZP980 phone is the choice of those who are not ready to spend money on the flagship and are not afraid to order phones on the network.
External DSDA Modules
This solution applies to Apple devices. Despite the fact that from time to time there are rumors and patent applications on the Internet related to the support of two SIM-cards in the iPhone, today there is none. The Chinese came to the aid of the destitute with their next know-how, bearing the name NeeCoo Me 2.
The device is a small block in which two radio modules and two slots for SIM cards are installed. The gadget communicates with the iPhone via Bluetooth and allows you to make calls from two different SIM cards. You can make calls even if there is no SIM card in the smartphone itself, which means that NeeCoo Me 2 is suitable for all gadgets running iOS, including the iPad.