For small companies,The best price/performance is iEnsemble form FlashlineVive 4 and 8 analogue ports.
H323 compatible and works fine with all others “Big” vendors. Voice qualiti is same as you can have for 10xUSD. Equipment include GW+GK+PABX functions, and for afforidable price you can have Billing solution (prepai and postpaid).
Cisco all the way! We run AVVID IP phones on public IP for SME. For inbound and outbound Call Centers will use IAD 2421, 5350, 5800. Tried Clarent and VocalTec – a few years ago. Cisco is the only place to be.
Check out IP blue. They have some very good VOIP solutions.They have a H.323 client and a Client that emulates Cisco 7960. This is very useful for mobile workers who may want to VPN into their workplace and still make calls.