What Is a SIP Trunk

Essentially, a SIP trunk is the virtual version of an ISDN phone line and enables organizations to upgrade their existing PBX infrastructure to use VoIP functionalities. This technology is becoming increasingly popular as the need for analog lines becomes redundant for many businesses who have migrated their traditional office telephony setup to a more flexible, scalable environment.

‘SIP’, which is short for Session Initiation Protocol, is an application layer protocol that lets you run your phone system over an internet connection as opposed to legacy systems and traditional phone lines. A "trunk" is a line or link that carries signals and connects nodes in a communications system – in other words, a pipe that carries the data channels inside it to connect two locations. 

How Does SIP Trunking Work

A SIP trunk is, in essence, a digital alternative to the analog phone line that many businesses historically used to make phone calls. SIP allows organizations to connect one, twenty, up to thousands of concurrent channels directly to an IP-enabled Private Branch Exchange (PBX), enabling those within the company to make long-distance phone calls via the internet. SIP trunks utilize a packet switch network, in which voice calls are broken down into digital packets and sent across a network to the final destination.

While for landlines a session simply consists of voice signals, SIP allows companies to transmit and receive different types of data such as voice, images, videos, documents, and other forms of media. 

What Is a SIP Trunk Provider

A SIP Trunk provider allows businesses to connect their in-house IP PBX systems to the PSTN (Public Switched Telephone Network). Company’s use SIP Trunk Providers to make outbound calls and receive inbound calls. Many providers offer much more than that. CM.com’s Voice Management app, for example, lets you scale up whenever you want using a convenient cloud interface, easily manage and monitor your outbound and inbound calls, and observe real-time insight into your voice data, including volume, destinations, cost, and quality statistics.

What Are the Benefits of SIP Trunking

Low Call Charges

SIP trunking allows telephone calls to be made over the internet. The most efficient route is chosen and there is no need to set up a dedicated line over the PSTN for the duration of the call. Compared to calls made over traditional telephone lines, this approach saves resources and significantly reduces call charges.

Quick and Easy Implementation of VoIP

SIP trunks are easy to install and configure. Companies can benefit from VoIP advantages such as flexibility and cost savings - without restrictions or cuts to their business processes.

Maximum Investment of Existing Infrastructure

SIP trunking allows businesses to use their existing non-IP infrastructure - including PBX equipment - for as long as possible, in turn enabling them to maximize their investment.

Lower Infrastructure Requirements and Costs

SIP trunking makes it possible to move to cloud-based PBXs, which reduces the need for in-house hardware, software, and support.

Future-Proof Telephony

With SIP trunking, the upcoming ISDN switch-off can't hurt businesses because they have the option to upgrade their infrastructure from ISDN-dependent PBXs to VoIP-enabled systems. By making your telephone system fit for VoIP today, you can ensure that you will be able to maintain your usual work processes even after ISDN is switched off.