Dual SimHave you ever found yourself with two separate mobile phones or one phone but two SIM cards ?

Perhaps one mobile phone for work, or business, and another mobile phone for private, or personal use.

Similarly, perhaps one mobile phone but two SIM cards - again one for work, or business use, and the other SIM card for private or personal use.

In this article brought to you by SIMsurprise.co.uk we give you a brief introduction to the concept of Dual SIM Mobile Phones.

What is a dual SIM Phone ?

A dual SIM Mobile Phone is simply as the phrase sounds - a single mobile phone with the facility to switch between two different SIM cards.

Types of Dual SIM Phones - Active and Standby

In their early development, an adapter containing two SIM cards would be attached to a "standard" Mobile Phone so that two SIM cards could be used without physically removing one SIM card and then inserting the alternative SIM card.

In this example, only one SIM card could be active at any one time - by this we mean that only one SIM card could be in actual use by making and receiving calls and text messages at any one point in time.

While one SIM card was in use, or active, the other SIM card would be inactive - or in Standby.

This is referred to as a Standby Dual SIM Phone. The currently un-used SIM card itself can be referred to as the Standby SIM, or sometimes as the Ghost SIM.

As technology has progressed it is now possible to physically place two SIM cards within your single Mobile Phone handset.

Both SIM cards can be active simultaneously. In this example - both SIM cards are continuously active - both are available to receive calls or text messages.

This is referred to as an Active Dual SIM Phone.

Standby Dual SIM Phones

Several types of adapter are available on the market - to go into any great depth of detail on each and every one of them is beyond the scope of this article. We will however explain the general concept of operation.

Unlike early versions which required your mobile phone to be switched off and then on again in order to change from one SIM card to the other, newer phones allow SIM cards to be changed by means of a Menu - in this case there is no need for your Mobile Phone to be switched off.

Active Dual SIM Phones

Possibly the most versatile of the two types of Dual SIM Phones.

This type of Mobile Phone has extra circuitry built into it, which does not add a great deal of extra weight or size to your Mobile Phone - such is the advancement of micro technology.

The added circuitry, in effect, produces two Mobile Phones within one casing - sharing some common features, such as the battery - so two phones in one, but not necessarily twice the physical size of one phone.

One drawback of early Active Dual Sim Phones is that the battery life was shortened because, in effect, the battery had to support two phones.

This has been overcome by increasing the size of the battery.

Active Dual SIM phones allow calls to be received on either phone number (each SIM card will have its own unique phone number) at any time, so long as an active call is not in progress on that specific SIM card, and hence phone number, at the time the call is being made.

So, a caller can call you on either your business number or personal number at any time and you will receive the call without having to do anything to your SIM cards.

Full control of which SIM card you are to use to make a call, or send a text message, is typically carried out by means of a menu system, similar to the menu system that perhaps you are already familiar with in terms of accessing messages, contacts, clock (time and date), etc.

Advantages of Dual SIM Phones

  • You no longer have to carry two completely separate handsets with you;
  • You do not have to change the SIM card by removing the back cover and battery;
  • One business SIM card, plus one Personal SIM card - one handset;
  • Price plans - one SIM card for making voice calls - the other SIM card for sending text messages;

Both SIM cards may or may not be connected to the same Network - they can be the same network, or two different networks - your phone, your use - your choice.

Perhaps the option of a contract calling plan on one SIM card and a Pay As You Go (PAYG) plan on the alternative SIM card might be a feasible option for some users who perhaps might want to share their handset with another household or workplace member.

Perhaps contract for your business number and Pay As You Go for your personal calls.

The combination options might be only limited to your own ideas and situation.

Instead of using one SIM card for business and one for personal use, you could use one SIM card for making voice calls and the other for sending text messages.

Why ?

Maybe one network has a cheap voice call tariff and the alternative network may have a cheaper text message tariff - cue, one SIM card for voice calls - the other SIM card for sending text messages.

Disadvantages of Dual SIM Phones

At the time of writing this article, the author is able to think of one major disadvantage.

  • If your handset becomes damaged, or lost, you lose use of both SIM cards until you make alternative arrangements for either a replacement handset for each SIM card, or a replacement Dual SIM Phone.

The future ?

The first mobile phones were large, heavy, and perhaps cumbersome - however they were a useful technological step in their day, even if the only time you will see them now is when visiting your museum.

Mobile Phones became smaller, lighter, more reliable and more popular, with ever increasing features and functionality.

In perhaps just a few years will the Dual SIM phones of now be museum pieces ?

Tri-SIM (triple-SIM) devices are already being developed and put onto the market where your mobile phone, or PDA, can have three SIM cards.

Business Idea

If you have a dual, or triple, SIM phone handset you can use your handset with your business SIM card and your personal / private SIM card - simply swap between SIM card as appropriate.