For security, you can enable associate a personal identification number (PIN) to your SIM card. To remove a SIM card from one handheld and use it in another, you must enable the security PIN first. It is very easy to pop a SIM card into a shiny new replacement phone and start using it straight away, which is one of the reasons why mobile phone theft is on the increase.
To enable SIM card security on the handheld
1. From the handheld Home screen, select Options
2. Select SIM Card. The SIM Card screen appears.
3. Click the trackwheel and select Enable Security from the menu.
4. Enter the security PIN you want to use.
5. Click the trackwheel and select Save.