A 'locked' mobile device is one that has been restricted by software so that it can only be used with a single network or carrier.
Mobile phones are used to be heavily subsidized and carriers wanted to discourage people switching networks or shipping phones to other countries. But, even unsubsidized devices (the current practice) are locked - because, really, what carrier wants to make it easy for you to use their device on another carrier?
'Unlocking' a phone means that it can be used with another SIM card/carrier - and in another country. But the unlocked handset may still display the original network's branding and may not support features of the new carrier. Most phones can be unbranded by uploading a different version of the phone's internal software or 'firmware'.« Back to Glossary Index