# What is SIP Trunking?

Put simply, SIP trunking is how businesses connect their phone systems to the wider telephone network using the internet, replacing the need for traditional, physical phone lines. It’s key for making calls to customers and contacts outside your organisation over the internet.

‘SIP’, or Session Initiation Protocol, is the technology that helps set up and manage the call session, and ‘trunking’ refers to the bundle of virtual phone lines over your internet connection that link the business to the PSTN (public switch telephone network).

# How does SIP Trunking help your business meet accessibility standards?

In my opinion, SIP trunking, by enabling modern and flexible communication platforms, helps unlock a whole new area of accessibility expectations for businesses. It contributes to democratising easy, cheap, and reliable connections between customers and businesses. With the extensive range of features and capabilities found in the communication systems that SIP trunking supports, businesses can better cater to increasingly diverse user needs.

If you’re one of the few that don’t already know how SIP trunking can help your business meet accessibility standards - allow me to enlighten you! Here are just a few ways that integrating SIP properly supports efforts to align with W3C’s POUR guidelines and can make your business industry-leading in accessibility standards and user experience.

# Perceivable

Making content perceivable means “information and user interface components must be presentable to users in ways they can perceive”. In this context, SIP trunking enables the use of modern communication tools and software (like Microsoft Teams for external calling) which offer multiple ways for users to perceive content. Features widely supported on these platforms, such as meeting chats during calls, call recording, and auto closed-captions, give customers many ways to get the best out of calls. (Side note: enabling Closed Captions is a fantastic accessibility win, directly addressing WCAG criterion 1.2.4 for live synchronized media).

# Cost-Effective

SIP trunking often saves businesses significant money and time compared to older phone line technologies, making it an easy yes when considering new customer connection methods. This improved affordability means advanced communication technology is more widely available for adoption, with plans for various budgets - meaning more organisations and their customers can reap the rewards. Furthermore, deploying flexible and modern digital infrastructures aligns with the aims of the UN’s SDG 9 (Industry, Innovation and Infrastructure), contributing to digital inclusion.

# Operable

By adopting a multi-channel approach in your communications (where voice calling, enabled by SIP trunking, is one option alongside chat, email, etc.), you’re giving users more choices and greater agency. They can choose to communicate in a way that suits them best. Thanks to the modern communication platforms that SIP trunking connects, customers are less likely to be limited to clunky, inflexible systems that sometimes exclude marginalised and vulnerable groups. With a number of available tools & softwares, users have more power to choose communication methods that support their diverse needs.

# Robust

The Robust principle focuses on compatibility with current and future technologies, including assistive technologies (AT). While SIP trunking itself is an underlying connection method, it enables the use of modern communication software (like softphones and UCaaS platforms). These platforms can often provide better compatibility and integration with assistive technologies (such as screen readers or alternative text input methods like RTT) compared to older, hardware-based phone systems connected via traditional lines. This helps reduce frustration and potential exclusion in the customer experience.

# Final Thoughts

By no means am I an expert engineer or telecomms specialist, but I can tell you where good UX and accessibility practices have been applied. SIP trunking is a great example of a foundational technology that is often underappreciated, even though it quietly helps break down communication barriers by enabling more modern, flexible, and potentially more accessible communication systems. So - next time you’re making a call from a platform like Teams to a regular phone number - take a moment to appreciate the technology enabling that seamless connection without relying on old-fashioned phone lines plugged into your office wall!

Sources:
https://sdgs.un.org/goals/goal9 https://gammagroup.co/ https://www.w3.org/WAI/fundamentals/accessibility-usability-inclusion/ https://www.itu.int/en/Pages/default.aspx