A Class 5 softswitch (known in the UK as a Digital Local Exchange/DLE) is a type of hardware that VoIP providers, cell phone carriers, and PSTN carriers use to connect phones (and other devices) to each other. There are five classes of switches, one through five. The number has nothing to do with the quality or newness of the switch, but the area. Class five switches connect to end users; classes two through four connect cities, towns, and even states; and class ones are international gateways. Class 5 switches also are the hardware that makes many of the call features of VoIP possible.
VoIP providers use a specialized type of class 5 softswitch, which is called an “IP switch,” a “VoIP class five switch,” or some variation of that. VoIP class 5 switches work through the SIP protocol. When you make an IP call, what you are actually doing is connecting through the internet to your provider’s softswitch. The softswitch routes the call to the correct IP address, SIP address, or DID number.
The class 5 softswitch enables the call features common to every business and residential VoIP provider: auto-attendant, call forwarding, call rules (find me/follow me/DND), call transfer, call waiting, caller ID, conference calling, e-911, enhanced voicemail, in-network calling, music, ring/hunt groups, UCC, videoconferencing support, virtual numbers.
For the VoIP provider, the class 5 softswitch meters minutes, and can bill customers automatically. One thing to keep in mind is that any phone can connect to the class five softswitch. VoIP providers can make money selling international calling minutes using a calling card. Another advantage for the VoIP provider is that it can be installed on any server, and it does not have to be on a customer’s premises. Your VoIP provider is “hosting” your PBX by having the softswitch collocated in a server farm that they own or rent.