Dual/Tri-SIM Phones: Important Features

The dual-SIM or tri-SIM cellphone is a relatively new type of mobile phone, especially to consumers in the United States. These handsets contain two or three card slots, and enable you to use multiple SIMs from different carriers - and even from different countries - at the same time. This means you'll only need to carry one phone, rather than trying to juggle two or three.

If you travel a lot, or have a cellular account that restricts your cheap calls to a small geographical area, you can also cut down on roaming fees by buying another SIM card and using it alongside your regular number. In addition, the ability to have two or three numbers on different frequencies active simultaneously means you can always be confident that you'll be within range, no matter where you go.

Before you purchase a dual-SIM or tri-SIM phone, there are a number of things you need to know. Like all high-tech electronic gadgets, the technology used in this type of cellular phone is constantly undergoing upgrades. Early dual-SIM cellphones were, frankly, rather gimmicky, with their dual card holders and adapters that only allowed you to use one number at a time. Many adapters required the user to cut their SIM cards to fit, which was quite a risky operation, and some people ended ruining their cards.

The latest dual- and tri-SIM handsets have none of these problems, however. You can now buy truly easy-to-use phones with two or three card slots that you switch between just by pressing a key or entering a simple command. The new models all let you keep all your SIM cards active at the same time, or turn one or two of them off if that suits you better. When you're shopping for your multi-SIM cellphone, the terms you need to look for are DSDS (dual SIM dual standby) and TSTS (tri SIM tri standby).

All dual-SIM and tri-SIM phones are multi-band, meaning that they support several different frequencies, typically with each card working in a different MHz range. For example, a quad- band phone supports networks that operate on all four GSM frequencies in use around the world (850/900/1800/1900 MHz), making it ideal for international travelers.

There are also dual-band and tri-band models. If you're based in the U.S. or Canada, make sure you check that whichever phone you buy supports your network's frequency (850 or 1900 MHz). Many tri-SIM phones have two GSM card slots and one CDMA slot for the ultimate in flexibility and functionality.

In case you're wondering, industry experts say we're unlikely to see quad-SIM cellular phones in the near future because the extra battery power needed for more than three active cards would cause the device to overheat. Of course, more advanced batteries may well be on the horizon too, so you never know. Today's multi-SIM handsets do use more juice than regular cellphones, however. This is why some models ship with two batteries, or feature extended-use battery packs. You can also conserve power by switching off SIMs you're not using.

While a few large handset manufacturers are starting to release dual/tri-SIM phones now, it's the Chinese electronics producers that are leading the way in this product category. Multi-SIM mobiles have been popular in Asia for a few years now, and there are many different models available. In North America, you can buy all the latest models from online electronic retailers that import directly from the factories and sell at very competitive wholesale prices.

In addition to the features outlined above, these top-quality phones are equipped with an array of features that would satisfy even the keenest gadget freak. Large touchscreens, with or without keyboards, are common, as are MP4 players, Bluetooth, Java, cameras, analog TV antennas, FM radio capability and much more.