Dual NAM's means that you can have two different provisionings for the same phone. Your NAM information includes your phone nuraber (MDN/MIN), system ID info, and the PRL (roaming information--i.e., what towers/network your phone has service on).
The term NAM and "phone line" are synonymous. So in essence one phone can have more than one phone nuraber and phone line. Each NAM on the phone can have an entirely different phone nuraber associated with it. And because each NAM can have it's own PRL, this means you can do things like have one phone with two different providers on each NAM. I have done this many times: My phone, for example, can have one phone nuraber with Cricket and another with Verizon at the same time.
While I'm on Cricket, it works as expected. However, I cannot send or receive calls on Verizon until I switch NAM's. Then, that same phone starts working on Verizon.
The phone itself must support dual NAM's. That is--if the phone doesn't support it from the manufacturer--you aren't going to get more than 1 NAM to work ever, period. Also, while the phone may support dual NAM's, the carrier that sells it might disable dual NAM's. This may require you to unlock the dual NAM feature. Some Motorola phones, for example, require you to do a low-level "seem edit" in order to unlock the NAM select menu, while other phones from other manufacturers can be changed using software like QPST.
Most Verizon LG phones support dual NAM capability without any real modification--you just need to be able to program each NAM separately.
With the right tools, you should be able to figure out how to get Dual NAM's working on your phone, if that's what you're interested in doing.
Hope this helps answer your question. Cheers! :buddies: