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A beginner’s guide to SIP trunking

ISDN, VoIP, PBX… In the world of communications, there’s more than a few acronyms knocking about, and SIP trunking is another one to add to the list. But since there’s no escaping how important these terms are, we’ve put together a beginner’s guide to SIP to steer you through.

What is SIP trunking?

Let’s get the major acronyms out the way first. Session Initiation Protocol (SIP) is an application layer protocol used to establish and terminate data and voice transfers. It’s a type of Voice over Internet Protocol (VoIP), which, refers to calls delivered over the internet. SIP trunking is based on SIP, and uses a Private Branch Exchange (PBX) to send and receive calls. This is a replacement technology for the Integrated Services Digital Network (ISDN), a system that transmits data and voice digitally over physical wired connections.

Why do businesses need to be thinking about SIP?

It may well be the case that your business is currently using a PBX and ISDN to facilitate your calls. In which case, you might ask: what’s changed? Why can’t you just stick with it? When it launched, ISDN was a great option for businesses, because it can deliver both voice and data services over one line. Nowadays, with cheaper and more versatile options widely available, ISDN is a dying technology – BT plans to switch off its IDSN network altogether by 2025.

As a result, many businesses have already made the switch to SIP trunking. It’s flexible, quick to install and provision, and can even be combined with a SIP trunk call manager for full control of your inbound numbers. But, like most relatively new technologies, there are some common misconceptions about what SIP trunking delivers. We’ve tackled some of the most common queries below.

Is SIP trunking expensive?

Good news if you’re considering a switch from ISDN – not only is SIP less expensive to maintain, it’s also cheaper on a day-to-day basis. You could save up to 50% on line rentals and 25% or more on call costs – if you’re keen to pin down a more exact figure, check out our price comparison calculator. Gamma SIP trunking also offers free internal calls, which is a handy feature for medium-sized businesses.

Does SIP trunking provide good call quality?

One of the common misconceptions around SIP trunking is that it offers low call quality. This might have been the case when VoIP first launched, but advances in technology mean call quality can now be crystal clear – providing you have the right data services in place.

Can SIP trunking support business continuity?

Damage to lines, a power cut, or even just an office move – there are all sorts of things that might lead to your business being out of touch. When your customers can’t get through, the damage caused can be pretty significant, whether that’s a financial impact or loss of reputation. Fortunately, SIP trunking delivers robust business continuity and can handle emergencies with ease, because calls can be quickly rerouted to an alternative location.

Is SIP trunking flexible enough to support growth?

For mid-sized businesses, growth can be a challenge, as you strive to tackle enterprise-sized problems without a matching budget – and all while keeping services ticking along as usual. SIP trunking can support growth in exactly this way, allowing you to add new lines and locations without noticeable disruption or a big capital outlay. And should you outgrow your premises altogether, you can even keep the same numbers when you move.

Can SIP trunking be part of a Unified Communications (UC) strategy?

More and more businesses are making the move towards UC – in fact, it was recently voted the third most important technology set to make a difference to business success. SIP trunking can support a UC strategy, as different devices can be integrated with the network.

Making the move to SIP trunking

SIP trunking isn’t the only option out there, of course – if you don’t have a PBX, cloud-hosted telephony could be the future of voice for your business. And if your organisation is currently relying on ISDN, there’s still plenty of time before it becomes fully obsolete. But given the benefits of this technology, there’s no reason to delay.

Ready to make the change from ISDN to SIP trunking? Download our eGuide which covers the fundamentals, from what SIP is to what it represents in terms of business opportunity.