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Types of Multi-SIM / Dual SIM
Dual SIM Holder
The first basic solution was a dual SIM holder, which allowed you to connect two SIM cards to your card slot. It is by far the cheapest of options but the main flaw is that it does not really work with both cards simultaneously. The problem is that one SIM is operating at a given time while the other, which is referred to as ghost-SIM, is unusable. The user can alternate between the two by turning the phone off and then back on. The other possible downfall is the holder size which can be bigger than a normal SIM meaning it won't fit in some handsets.
MultiSim.co.uk
There are several types of multi-SIM or dual SIM adaptors available. They all allow one sim to be active, and to receive incoming calls at any given time. They dual SIM devices have various ways of switching from one SIM to the other. Some early versions required the phone to be switched off and on again to change from one SIM to another. More recent models allow the user to switch SIM cards via a menu or by keying in a numeric code, without switching the phone off.
With multi-SIM and dual SIM adaptors and phones you can now have two or more phone numbers without the expense of buying a second phone or the hassle of carrying two phones around with you.
The advantage of using two SIM cards in one phone is increasingly becoming a desirable option that people are willing to consider. Using both a personal and a business number with one single mobile handset, and saving money by combining two different plans or network carriers. You no longer need to carry two mobiles with you as manufacturers have been coming up with ingenious ways of dealing with the situation of using two Sims in one phone and switching between the two.
First came the dual SIM holder which evolved into dual SIM adapters used widely in many mobile phones. Dual SIM phones have recently started to appear on the market without the need for an additional adaptor.
The major mobile phone manufacturers seem disinterested in producing dual or multi SIM mobile phones, but small-scale manufacturers have taken to producing their own dual SIM mobile phones covering a small niche in the market.
Dual SIM Adaptor
The function of adaptors does not differ much from holders, as their function in pretty much the same. The main difference and benefit of the dual SIM adaptor is that it is the same size as a regular SIM card and therefore can fit in any phone.
But the main disadvantage is fitting the two SIM cards into the adaptor module which can be a challenge as you need to take the Sims out of their plastic holders and then place them in the adaptor. Cutting and puncturing your cards involves some level of risk but fortunately most dual adaptor dealers will do that for you upon purchase.
Some of the more recent models also allow switching between the SIM cards without turning the phone off. You still can't use the two SIM cards simultaneously.
Dual Sim Holder
Dual SIM Mobile Phones
The first dual SIM mobile phones did have two SIM card slots, but only one could be used at a time. The fitting of both SIM cards into the phone wasn't a burden any more and the phones were not locked making it possible to use two Sims from different network providers.
Dual SIM mobile phones are handsets which hold two SIM cards instead of the usual one. The main benefit is to carry only one handset in situations where you may be carrying two. You could for example be roaming in a foreign country with one SIM card with your usual number and the second could be a local countries network SIM card.
At home you could use one network or tariff optimized for peak time calls and another that gives free off peak minutes. Business people may wish to have two numbers active during the day, one for personal calls or incoming calls only, with a separate line for dialing out.
It is possible to buy dual SIM adaptors to covert your existing mobile phone to take two SIM cards, but these often require, modified phone casings or even cutting the SIM cards down to accommodate them. Some manufacturers like Samsung are starting to realize that there is a market for devices that hold two SIM cards. The Samsung have developed D880 Duos is a slider style phone with 3.2 megapixel camera and bluetooth.
Unlike early versions, these recently designed dual SIM phones can have both cards active simultaneously to make and receive calls or send/receive SMS messages. The user can select using either card to use for mobile browsing, e-mail and other multimedia.
Dual Sim Cards
Some companies came up with the idea of mechanically connecting two mobiles in a way that will allow using both. With the combination of two mobile phones, some had two screens and keypads.
As an example of the latest dual SIM mobile phones on the market is the WND Duo 2000
It not only stores two SIMs, but it is actually capable of operating them as on the single phone with the push of a button.
With both SIM cards active, you can place and receive calls on each of them at any time. Other types of such phones have two dial buttons - one for each SIM - so you can easily choose the SIM card of choice for a particular outgoing call.
They are also working on another dual SIM mobile phone worth looking at the WND Telecom's Wind DUO Atom. This dual SIM mobile phone is equipped with a gravity sensor for seamless alternation of the SIM cards.
How does Multi Sim work?
You have a main number that people can contact you on, and up to an additional 10 Sims for other mobile devices via a routing number, to which you assign an ID number.
How do I nominate the device?
Incoming calls to your published number are routed to the SIM number that you have nominated. Generally you can just type a code into the mobile device you want to receive the calls to route them to that device. The device can be a pda, general mobile phone, car base cell phone or similar
Advantages of the Multi-Sim System
- Fast and efficient, no need to swap the SIM between your different mobile phones or other mobile devices.
- There is a reduction in cost as your extra Sims generally gets a lower line rental than your standard monthly charge.
- One single bill for all the multiple sim cards, ,making managing your bill much easier
- Improved communication as you can be contacted much easier no matter what mobile device you are using or where.
- Simultaneous use of your mobile devices with a single number. You could download e-mails onto your PDA while communicating with someone on your mobile phone at the same time.
Another Multi-Sim Option
Some mobile phone operators and networks have introduced a multi SIM option on their networks. The benefit of this multi SIM option is to
make and receive calls on the same number from multiple handsets without switching your SIM card from handset to handset.