The alarm|SIM CARD is a worldwide multi-network SIM card solution and may have a couple of UK phone numbers associated with it. The phone number provided to you at time of registration is the primary phone number and can be used to call and SMS your alarm panel. Your may find that when your alarm calls you or sends you an SMS that a secondary phone number is displayed, this is normal. You may however wish to store this number in your phone as "Home Alarm" for example so you can easily identify it as your alarm.