So, wow. I don't know if I'm allowed to cover this, but I will, and will remove it if requested.
PRL stands for Preferred Roaming List. Back in the day, when you bought a cell phone, it was essentially tethered to one tower. That tower was called it's home.
Technology progressed, and the ability to move from one tower to another was developed. This was called roaming, as the phone was roaming away from it's home. When you went from one tower to another, the call would drop.
Technology progressed some more, and the ability to keep a call connected while going from one tower to another was developed. This was called a handoff. This actually involves the phone knowing which tower it came from, which tower it is going to, and which tower it is currently on.
As more companies came out, they made roaming agreements. But how can a company like VZW guarantee service in areas that it has company-owned towers: That is, how do we (VZW), prevent our customers from using Sprint towers in areas we have adequate coverage in? (Roaming on other carriers cost a bit of money, and they do exist to make money, lol)
So they developed a Preferred Roaming List. Your phone knows what towers are in your area, which tower will provide you the best coverage, which towers to handoff to, et cetera.
All that, and it's only for the voice network.
Data runs separately. Two different networks, same towers.
*22899 Contains PRL information for the voice network. The difference between it and *228, option 2, is that *22899 contains data network information that has to be authenicated separately. This normally occurs when you make your first call on the voice (is95) network. It sends a data bracket at the beginning of the call that authenticates your esn for use on their (insert generation number here) network.
You would want to use *22899 for most data issues (texting excluded). It can also force PRL information on VZW phones with official OSes on them. It is particularly helpful to people running custom OSes (ie: Android), because it gives your phone the data information and authentication with pushing other software and updates that may brick your phone.
Anyway, hope that explains it.
