When people talk about a double subscriber identity module (SIM) card phone, they are usually referring to a mobile device that can hold and use two different SIM cards at once. A phone of this type allows consumers to receive calls intended for two separate numbers. The classifications of double SIM card phones are standby and active. In addition to being convenient, these devices can also help consumers to save money and facilitate easy communication for international travelers. While many consider these phones to be some of the best on the market, they have yet to gain momentum in many countries because of carriers' fears of adopting them.
A device that allows the consumer to switch between two SIM cards at will is called a standby dual-SIM phone. Introduced in the year 2000, these phones quickly became a high-end luxury that let business people receive professional and private calls on the same phone. While the standby double SIM card phone, in some ways, provided a means for convenience, it also required that the user actively switch between the cards. This could be a cumbersome maneuver for busy people.
Active dual-SIM phones let consumers receive calls directed to two numbers without having to manually switch between cards. The SIM cards can work natively with a device to provide a more streamlined reception and calling experience. The devices can be expensive, but the opportunity to carry just one phone instead of two can be worth the price for those who value accessibility above all.
Practically, a double SIM card phone has many uses besides convenience. People who adopt the device may use one SIM card for a calling plan and the other for a texting or data plan. Frequent international travelers can use a SIM card from their native country and another from the one that they are visiting to receive calls from both places without any additional cost to callers. In some cases, the extra card can be simply used as a means for backup if the first were to be damaged or compromised somehow.
Despite being popular and useful to a large number of consumers, many countries are still new to the concept of a double SIM card phone. This is a commercial issue more than a consumer one, as mobile carriers fear that devices that utilize two SIM cards will undercut their profits, since customers are likely to comparison shop for the best rate plan deals. It would be likely, then, that consumers would use two carriers for services on separate SIM cards, which would undercut both companies' profits. As the double SIM card phone gains momentum in developing countries, however, countries with competitive carriers are likely to adopt them into their available device inventory.