BlackBerry phones released before 2013 can be unlocked for free without PC software. I suggest clicking the links on a PC. For a 9720, or BB10 or Android phone, contact the carrier or an unlocking service.
1. Go to Options > Device > Advanced System Settings > SIM Card (OS 6/7), Options > Advanced > SIM Card (OS 5) or Options > SIM Card (OS 4). Type mepd and several items will appear. If Active or Enabled appears next to Network, the phone is locked.
2. Follow this guide, noting the IMEI.
3. Choose OS Engineering Screens > Device Info. Scroll and note the MEP.
4. Follow these PM instructions - you need a CrackBerry account. Don't download the software!
5. When you get the unlock key, go to the SIM Card menu (step 1). Type mepe or any of these codes, then enter the key. If 'Code accepted' appears, the phone is now unlocked!
