A dual SIM mobile phone is one which holds two SIM cards. Initially, dual SIM adapters were made available to use in regular mobile phones to allow them to contain two SIMs, and to switch from one to the other as required.
Dual SIM operation allows the use of two services without the need to carry two phones at the same time. For example, the same handset can be used for business and private use with separate numbers and bills; or for travel, with an additional SIM for the country visited. Using multiple SIM cards allows the user to take advantage of different pricing plans for calls and text messages to certain destinations as well as mobile data usage.
These phones have until recent years been largely eschewed by the larger phone manufacturers partly due to their close ties with mobile phone networks who would prefer that customers use only one network exclusively. However more recently manufacturers such as Nokia and Samsung have started producing these phones, targeting mostly business users and teenagers, but also users from developing countries.
Dual SIM devices can be recognised by the presence of two signal strength bar charts, which symbolically display how strong a signal is being received on each SIM's network. A symbol of a cross is usually displayed if one or both SIM cards are not inserted, since all devices can be used with just one SIM card.
Devices that use more than two SIM cards have also been developed and released, notably the LG A290 triple SIM phone, and even handsets that can run on four SIMs, such as the Cherry Mobile Quad Q70. Popular Indian mobile companies such as Karbonn Mobiles, Micromax Mobile, Spice, Lemon Mobiles, LAVA Mobiles have launched many feature phones with dual SIM technology. Even a few smart phones from these companies are dual SIM based.
Philips has produced Xenium 9@9w and 699 models with this capability, belonging to the restart-to-change-active-line generation. More recently, some phones have been produced that can natively work with two SIMs, both of which may be active at the same time. These are active dual SIM phones.
- 1 Pseudo-Dual
- 2 Dual SIM Single Standby (DSSS) / Dual SIM Shift
- 3 Dual SIM Dual Standby (DSDS)
- 4 Dual SIM Dual Active (DSDA) / Dual SIM Dual Call/Dual Talk/Dual Pass
- 5 Reception
- 6 See also
- 7 References
- 8 External links
Providing the convenience of using a second SIM slot only (as rule, it has "no major" slot for this), without needing both SIMs install to the owner's respective mobile service providers (MSPs). Although SIM card holder are seldom spoil.
Dual SIM Single Standby (DSSS) / Dual SIM Shift
Initially for basic phones, which have two SIM card slots, but with only one SIM standby at a time (able to receive calls) and shown on the screen; users need to manually switch to another SIM by choosing from a menu.
Dual SIM Dual Standby (DSDS)
- It is also known as Dual SIM Standby (DSS)
Automatic allow both SIM cards to be on standby waiting for a call/data connection. When a call/data is established on one SIM card, the other is no longer active. Callers to the other SIM will hear a message that the phone is switched off or they'll be redirected to voicemail if any. Although, starting from 2012, the phones using chipset MediaTek MT6575, can provide the ability to receive a call on both SIM cards even when an active data connection is established on first SIM card, using only one transceiver.
- Negligible battery power usage as compared to single SIM 3G active phone.
- Those phones with MediaTek chipset, when using one SIM for active data (PS) connection, it would automatic switched to the other SIM incoming voice (CS) call.
- SIM1 may support 2G/3G while SIM2 may only support 2G to prevent interference and saving battery power.
- In order to receive calls on both lines even when a first call is in progress, the user should enable call forwarding to SIM1 when SIM2 is disconnected at the carrier’s network. This can be done manually on any phone, regardless of manufacturer, e.g. enabling call forwarding to SIM1 when SIM2 is disconnected. Call forwarding must be provided by the carrier, who will often charge a flat fee for this service; the subscriber may also be charged for call forwarding on a minute-by-minute basis, depends on the subscription agreement.
- All dual SIM dual standby phone cannot make or answer calls/datas on both networks at the same time.
- Negligible higher retail cost as compared to similar Single SIM phones, as build up process is almost same. The higher demand in emerging market, makes the technology cheaper today.
List of (DSS) Phone model
- Freeyourmobile M180
- K-Touch A982
- Lenovo P770, P780 (4000mAh capacity)
- LG GX200
- Motorola Moto G (GSM XT1033)
- Nokia C2-00, X1-01, C2-03, C2-06, 301, Asha 200, 210, 500
- Philips Xenium X100
- Samsung Champ Duos E2652, GALAXY Ace Duos (GT-S6802), S Duos (GT-S7562), Grand Duos (GT-I9082)
- Xiaomi Hongmi (Red rice)
- HTC Desire 601 dual sim
Dual SIM Dual Active (DSDA) / Dual SIM Dual Call/Dual Talk/Dual Pass
- It is also known as Dual SIM Active (DSA) or Dual SIM Full Active (DSFA)
These phones have two RFs, two SIMs and two Modem Stacks hence it allows the device to be connected to both networks at the same time, hence simultaneously allow calls or datas to be received on either number at any given time.
- The device can switch between two calls without dropping either, so while you are on a call you can still receive calls on the other number. These devices have two transceivers. Both SIMs are able to receive calls; once an active call on one SIM is established, a call can still be received on the other SIM. If the user likes, he or she can switch between two calls without disconnecting either of them.
- All such phones have two transceivers built in, SIM1 may support 2G/3G while SIM2 may only support 2G to prevent interference and saving battery power.
- Battery life (talk time and standby time) of active dual SIM mobile phones is reduced, typically by about a third. For instance, device manufacturer Samsung declares a 1/3 less standby time when used with two SIM cards.
- Thicker base to compensate for the shorter battery life, some dual SIM phones ship with better capacity batteries or these phones may also be supplied with two battery packs.
- Higher retail cost due to complicated build up process using two Modem Stacks.
List of (DSDA) / (DSFA) Phone model
- Samsung D880/D780, B5722, B7722 
- LG GX500, Lg GX300
- Acer Tempo DX90 (E-TEN glofiish DX900) known as first DSFA smartphone in the world.
- ZTE U960
- Gigabyte GSmart Simba SX1 [NA-US]
- HTC One SU T528w (Desire 400), E1 603e, Desire 606w (Desire 600), Desire 7060, One 802w (One DS), One Max 8060
- Lenovo K910 VIBE Z Dual Sim Full Active Snapdragon 800 Quad Core 2.2GHz 5.5 inch FHD DSFA [NA-US]
 Per amazon.com comments B7722 is not dual active, and SIM 2 does not work in the US. [NA-US] Not available in the USA.
Dual SIM are getting popular due to competitive plan and network coverage. Some sub-contract Chinese companies can supply inexpensive dual SIM mobiles, mainly in Asian countries. The phones, which also usually include touch screen interfaces and other modern features, typically retail for a much lower price than branded models. While some such phones are sold under generic names or are rebadged by smaller companies under their own brand, numerous manufacturers, especially in China, produce dual SIM phones under counterfeit trademarks such as those of Nokia or Samsung, either as cosmetically-identical clones of the originals, or in completely different designs, with the logo of a notable manufacturer present in order to take advantage of brand recognition or brand image.
Samsung in their marketing materials has introduced a term "Dual SIM Always on" feature. The term is misleading, since it does not mean what is says – both SIM cards are NOT always on, their hardware doesn't support this. All Samsung phones with this feature "Always on" are regular DS Standby phones with one transceiver (radio) – the second SIM is disconnected when a call is in progress on SIM1 and vice versa. The user should enable call forwarding to SIM1 when SIM2 is disconnected in order to receive calls on both lines, always.
Nokia has launched two dual SIM phone models, the C2-00 and X1-01. Both are 2G phones. Nokia will launch more dual SIM devices such as the C2-03 and the C2-06, featuring a "Touch and Type" user interface with "Easy-Swap SIM" facility. All of the models produced so far are Dual SIM Standby phones - they have only one radio. Nokia at this point (January 2013) has no publicly announced plans to produce any Dual SIM Active phones. Also all current Nokia Dual SIM phones use the Series 40 interface. In the first quarter of 2013 alone Nokia sold 16M dual SIM Asha phones. This and growing customer demand for dual SIM phones motivated Nokia to release the Asha 500 in both dual and single SIM versions.
For Lenovo, which bought IBM PC business in 2005, the next big challenge was finding a new source of revenue by expanding its smartphone business. "We must make another successful transition. Smartphones are our new opportunity", Chief Executive Yang Yuanqing said in June 2013. "Back in 2005, who would have thought that we could be No. 1 in the PC business? We were nobody. So what makes you think we can't do that in smartphones?", said Senior Vice President Milko van Duijl, a Dutchman who joined Lenovo in 2005 from IBM.
In January 2014, for the first time in history, Lenovo challenge all premium brands when launched the Lenovo Vibe Z phone in China and world wide market. Lenovo K910S Vibe Z version turns out to be the fastest smartphone on the market at the moment and to be also a Dual SiM Full Active.
|Wikimedia Commons has media related to Dual SIM.|
- Dual mode mobile
- Subscriber Identity Module
- SIM cloning
- International Mobile Equipment Identity
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