We have a whole bunch of GXP 2000 phones here but now we're growing too big for just 4 incoming lines. We use Trixbox (asterisk) for the phone system with 4 analog lines coming into a Dell server.
Is there a way that these Grandstream GXP 2000 phones can handle 8 lines? How does that work? Is there some kind of configuration that can be done in Trixbox when we do move to 8?
The number of lines are the number of active calls on that specific phone extension, depending on the business you'll want to stick them in a queue like recommended before and distribute them to different people/departments.
In reality except for a receptionist, the use of more than two lines is usually worthless, and I'd usually stick them behind a queue (and probably a auto attendant...) too.
You can use a queue and stack your incoming calls.
That way you can handle more than 4.