If you have Sprint, it will only allow to camp on a Sprint system (this can be adjusted in the Roaming Options of the phone, to allow for Sprint Only, or Automatic which then allows Sprint Roaming Partner networks to work as well) but will not camp on Verizon, US Cellular or Cricket CDMA networks.PRL files can also be used to identify home networks along with roaming partners, thus making the PRL an actual list that determines the total coverage of the subscriber, both home and roaming coverage.It took a few years to get direct OS support for it (Anyone remember calling Sprint to get your PRL update "flagged"?), but we did with later versions of Windows Mobile.Updating the PRL on your cricket phone is actually quite easy and takes little effort to complete. Press "2" when the audio recording prompts you for a menu decision.
Regularly updating the PRL will help improve your network coverage and reduced the amount of "dead zones" and dropped calls you receive. Unplug the phone once the battery is fully charged. Depending on your phone, you may be able to immediately start dialing from your home screen.
If you've ever had an issue where your phone isn't successfully connecting to the network even though you're in a good coverage area, there's a strong chance that an over the air update will get your phone working again.
Every time your phone reaches out to the cellular network and downloads information related to your phone’s access to voice, text and data services, you’re completing an over-the-air update.
So it's nice to know that in Windows Phone 7, part of the CDMA integration that came with the 'No Do' update on the Sprint Arrive was PRL and Network Profile support.
Over the air updates are important because they synchronize your phone with the network.