Trying to work out a low cost IP phone system to connect to about 12 - 15 employees. Moving offices, currently have NBN moving to ADSL2+ and most likely physical phone lines into the building so no VOIP. Most likely have 4-6 external lines 1 fax. For an accounting firm. What sort of systems should I look at implementing that can just plug into phone lines coming in, go onto the network and connect to all the IP phones. I am a bit new to the whole IP phone solution thing so not 100% sure what solutions are most commonly used by small-medium business. We have 2 servers on site could use the application server if needed.