Often you hear about IP Telephony and VOIP, and the two terms are mistakenly synonymous. In fact the difference is substantial. The first technology to be marketed was VOIP: with the advent of the Internet and the wave of online service success, many manufacturers saw the network as an opportunity to spend less even in telephony. That is, with the bandwidth increase, Internet voice support has become a reality at relatively low cost, relatively because it gives priority to voice over data, equipment to buy, and so on. they have a not negligible cost. This approach was that of VOIP. That is, voice over IP - voice over IP, which started to make us "dream" about the possibility of calling over the Internet.
IP Telephony makes the switchboard a network server, even clustered and virtualized, and that telephones are network nodes: the benefit is no longer on the reduction of telephony costs, but goes in the direction of reducing the costs of management and maintenance. In small realities, the purchase of an IP switch, combined with the mandatory replacement of telephones, has a cost comparable to the maintenance fee of the existing switchboard. With undoubted benefits of management.
Today we talk about voip switchboards, voip open source switchboards, voip pbx switchboards, but above all voip asterisk switchboards: we are there!