Dual Sim.

Dual Sim is a Facility to have 2 GSM phone numbers in one sim. To use this facility your phone must be a Dual SIM compatible phone, the way to support this Line One, Line Two Facility. The user can get the Phone number from the service provider. Thus allowing the customer to be reached via the Line Two if it is not possible to reach through Line One.this is also called as Universal simcard (to hold two sims in one).