What is a "SIP trunk" in 3CX?

A SIP trunk in 3CX refers to a virtual phone line that facilitates Voice over Internet Protocol (VoIP) connectivity. This technology allows businesses to make and receive calls over the internet instead of using traditional telephone lines. SIP, which stands for Session Initiation Protocol, is essential for setting up and managing communication sessions for voice calls, video calls, and other multimedia transmissions over IP networks.

Using a SIP trunk provides numerous advantages, such as reduced costs, increased scalability, and flexibility in managing phone services. With a SIP trunk, multiple calls can occur simultaneously over a single internet connection, making it an efficient choice for businesses looking to optimize their telecommunications without the need for extensive physical infrastructure.

While the other options reference communication methods or technologies, they do not correctly identify the nature and function of a SIP trunk within the context of 3CX.