said by forumsviewer:
So basically the inbound phone numbers run through a different system or ciruit than the outbound? Meaning, outbound is 100% VOIP and inbound could be POTS or something else? Both inbound and outbound would be controlled by Asterisk (FreePBX)?
I guess I don't know what voice PRI (or POTS) circuit means and how that is different than SIP trunking.
Inbound calls would come in on the T1 PRI. Some providers have very good long distance rates and a large pool of included minutes, so you might even be able to use it for long distance as well. You could certainly use it for local calls.
You can use VoIP for as much or as little outgoing calling as you want. Asterisk (among other systems) lets you pick where to route calls based on the phone number, so you could send local calls out the PRI, and long distance or international calls through the carrier of your choice. Or, you can send all outgoing calls through a VoIP provider, and 911 through the PRI... this way, your PRI capacity will not be used up with outgoing calls. If you have issues with VoIP, you can just re-route outbound calls back through the PRI.
You can also use POTS lines, but for anything more than a handful of lines, a PRI is a much better choice. It lets you set outbound Caller ID, handle DIDs, and more.
One word of caution: I recommend becoming familiar with the technology (or find someone who is) before setting it up. To get started, see »en.wikipedia.org/wiki/Primary_Rate_Interface
. It is important to understand the technology for troubleshooting and implementation purposes.