Onsite Phone Switch device that connects office telephones in a business with the public telephone network.
Route incoming calls to the appropriate extension in an office, and to share phone lines between extensions.
Over time, many functions have been added, such as automated greetings for callers using recorded messages, dialing menus, connections to voicemail, automatic call distribution (ACD), teleconferencing, and more.
Delivers PBX functionality as a service, available over the PSTN and/or the internet. The first hosted PBX was introduced to the market in late 1997 by Virtual PBX. Instead of buying PBX equipment, users contract for PBX services from a hosted service.