The term PRL actually refers to file stored in your phone. This file directs the phone to find alternative networks to operate on when the primary operator cannot be reached. Updating the PRL will store in the phone which are the most up to date, current networks to operate on. In order to operate on another carrier’s network your primary service provider must have a roaming agreement with other carriers.
Almost all phone carriers, such as Oxygen, Locus, Cingular, Verizon, etc. have roaming agreements with other major service providers.
Generally PRL updates are done on CDMA and PCS phones. GSM phones do not need PRL updates. Without a PRL file your cell phone would only receive service on its primary carrier’s network. Eliminating coverage in areas where your carrier does not receive service.
Read more about PRL updates.
