A dual sim mobile allows a cell phone user to have two lines of service on the same phone. Many dual sim mobiles allow a personal and business number to be used on the same device. A cell phone user can receive incoming calls through two separate numbers, and place calls through a work and personal number.

Dual sim mobiles can be valuable in rural areas and when traveling abroad. Some world phones incorporate two or more sim cards, allowing the user access to different cell phone networks. This can allow one phone to receive coverage over a huge area. Some models allow interoperability between different networks: one sim card provides 2G access, while another provides 3G access.

While there are many benefits to using more than one sim card, there are some disadvantages. Two sim cards usually increase the power drain on a battery by 30%, reducing talk and standby time. In addition, a dual sim phone may be slightly heavier than a single sim phone. Some require separate antennas and transceivers, contingent on the cell phone networks being used.

Some Chinese manufacturers have released triple sim cards, which allow increased coverage in some areas. Many parts of China don’t have consistent cell phone coverage from a single provider. By using a triple sim card, it’s possible to have consistent coverage in many areas.

There are some limitations to dual sim mobiles. In addition to a shorter battery life, a dual sim phone will require two separate cell phone plans. For users trying to increase coverage through multiple cell service providers, a dual sim mobile will not allow one to have a single unified telephone number. A cell phone user will have a different number assigned for each cell phone service line.

Dual sim mobiles are only available on GSM networks. CDMA networks don’t use a sim card in a telephone: they rely on a unique ID embedded inside a phone, called the ESN. It’s illegal to change the ESN in a phone. Some manufacturers are actively looking for ways to incorporate multiple ESNs into a single cell phone, but no devices are publicly available yet.

Cell phone technology has changed dramatically over the past few years. While a dual sim mobile may not be appropriate for everyone, it can be valuable. It allows for increased cell phone coverage, better range, and seperate service lines one a single device.