Hello! [Situation] I am working for a small company (about 15 employees). We take calls for sales and technical supports. We have an old PBX with minimal basic functions (transfer, hold, 3 person talk, etc.). Our president is considering changing our phone system into VoIP + VoIP PBX. [Questions] 1. Is VoIP mature(stable) enough now? I visited artisoft.com and found the following article which is negative about VoIP. Src: [URL]http://www.artisoft.com/pdf/SoftwarePBXWP.pdf[/URL] <snip> Internet Protocol (IP) PBXs As Voice-Over-IP technologies improved, several vendors introduced IP PBX products that managed all communications over a business IP network. Because IP standards were still evolving, each vendor interpreted them differently or ignored them completely, creating telephones and routers that were incompatible with those of competing vendors. This resulted in proprietary and sometimes very expensive telephones, routers and hubs. In addition, the vendors provided only very basic application sets and their proprietary architectures provided little incentive for 3rd-party developers to create add-on applications. Essentially, the IP PBX merely replicated the limited features and high cost of ownership of traditional proprietary PBXs within a data-centric environment. </snip> 2. Do we keep the current phone number after changing into VoIP? I have no idea how the IP phone is assigned a phone number. 3. Is it easy to maintain the VoIP system? Our current phone system causes no trouble. I fear that VoIP system may give lots of pains. What can we do if the Internet is down? 4. Can we use the current old PBX with VoIP? If VoIP-PBX is not good or is not worth going for, we might keep the current PBX and just go for VoIP. 5. Which vendor is worth checking out and how much will it cost? 6. How much money can we save with VoIP and what benefit else can we get? I would appreciate any help. Sam