The Session Initiation Protocol, sometimes known as SIP, is a type of signaling system used to regulate communication sessions. These conversations can be conducted using VoIP (Voice over Internet Protocol) or other platforms, which are often online or cloud-based. SIP is simply one technique of installing VoIP; its main advantage is that it establishes a direct connection between private or local telephone systems and the public telephone network. Individuals and corporations can now connect without relying on a traditional telephone line.

https://www.apptha.com/blog/be....st-sip-calling-softw

Best Sip Calling Software