what is a sip trunk

A SIP trunk is a virtual phone line that lets a business make and receive calls over the internet instead of using traditional phone lines. It connects a phone system like a PBX to the public phone network, so calls can be routed digitally.

Quick Scoop

“SIP” stands for Session Initiation Protocol, which helps set up, manage, and end voice or multimedia communication sessions over IP networks. “Trunking” means bundling multiple communication channels into one logical connection, which is why SIP trunks can replace several physical lines.

Why businesses use it

• Lower cost than many traditional phone setups.

• Easier to scale up or down without new hardware.

• Supports voice, and often video or messaging too.

Simple example

If a company has 50 employees but only 20 concurrent calls at once, a SIP trunk can provide those call channels virtually instead of installing 20 separate physical phone lines.

In plain English

Think of a SIP trunk as a digital bridge between your office phone system and the outside phone world. It does the same job as old-style phone lines, but over the internet.

If you want, I can also explain SIP trunk vs VoIP vs PRI in one short table.