Understanding Asterisk implementation better

We have reached a point where we have maxed out our traditional PBX system in our office. I am entertaining installing an IP-PBX to handle the expansion and eventually roll it out to all users. Asterisk seems to be the way to go as far as the IP-PBX system but I would like to make sure I understand the implementation requirements before I begin.

We have 3 voice lines and 1 fax line right now. We need to add more lines, so I am considering Broadvoice/Vonage/Etc for these add’l lines. When I order from them, I can just plug the “phone out” jack on their converter into an FXO port on my Asterisk server, correct? Is there a way to keep it all on IP/Ethernet?

I will also be able to let my traditional PBX talk to the IP-PBX. What is the best way to implement this?

The VOIP network will be on a dedicated 100mbit network that has no data traffic whatsoever. The server will be dedicated and only run Asterisk, DNS, and a couple of very small programs. Will this configuration should let me expand to 40+ users over time (assuming 1 in 4 will be accessing the system at any given time)?

Thanks for all of the help,


Look for a BYOD plan (bring your own device), this will allow you you to connect directly from your * box to their server over your internet connection, no FXO ports needed