# What is SIP trunking?
> Method of connecting a company's phone system to the public telephone network (PSTN) using the internet instead of phone lines

SIP trunking connects an on-premise PBX to VoIP services over the internet, replacing traditional phone lines.

## What is SIP trunking?
[SIP Trunking](/blog/sip/what-is-sip-trunking-benefits/) is a technology that allows businesses to send voice and other communications over the Internet using the [Session Initiation Protocol (SIP)](/blog/sip/what-is-session-initiation-protocol-sip-guide/).

"Trunking" refers to the aggregation of multiple voice or data connections into a single link for more efficient communication.

It connects an organization's on-site PBX (Private Branch Exchange) to the Internet, enabling calls to be made and received over the web, bypassing traditional telephone lines and reducing costs while providing scalability and access to advanced features.

## Related Terms
- [5G](/voip-glossary/5g/)