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What is SIP trunking and how does it work?

SIP trunking explained (and how it can benefit your business)

SIP trunking is a type of technology that lets you make calls over a data connection. Of course, there’s a lot of clever technology behind it but we’re not going into the technical detail here (SIP stands for Session Initiation Protocol, by the way). Instead, we’ll give you a layman’s overview of what SIP trunking is, how it works and the benefits it can bring to your business.

What are the benefits of a BT SIP trunk

BT SIP Trunks are cheaper than traditional phone lines, come with a generous call allowance, and have free calls between BT SIP Trunks. The pricing structure is really simple, and there’s no spend commitment.

How does SIP trunking work

It works with BTnet, our market-leading leased line broadband. BTnet is a dedicated internet connection that you don’t share with anyone else. Because this means less traffic on your line, you get faster speeds and more reliable internet connectivity. In fact, with BTnet you’ll get a 100% target availability SLA. When you’re using your internet connection to carry your voice traffic, it’s important that your internet connection is fast and reliable.

And because we own SIP trunking and the network, we can provide Quality of Service so you can be reassured that call quality will never be compromised. Quality of Service ensures calls are prioritised over other data traffic. In fact, your voice calls will have a dedicated bandwidth, so no matter how much other data you're consuming, your calls will never suffer.

You can have more flexibility with your phone numbers. With BT SIP Trunk, phone numbers are no longer tied to the local exchange. So you can have any number on the service, allowing you to market yourself locally across the country. And if you need to move premises, you can take your numbers with you, wherever you go.

You’ll also have more business continuity options. Calls can be redirected to another BT SIP Trunk number and can automatically re-route to any other backup or resilient BTnet you have. This can be a much cheaper disaster-recovery option than having a separate, dedicated voice back-up. 

What is the difference between SIP trunking and VoIP?

VoIP (voice over internet protocol) is a broad term for calls made over the internet rather than a regular phone line. It’s no longer considered a single protocol and has become a blanket term in the industry to refer to technologies transmitting voice over the internet.

SIP (session initiation protocol) is a signaling protocol used to control and support multimedia (video and text as well as voice) sessions over IP based networks.

Who is BT SIP Trunk suitable for?

You need to have, or be considering installing, a BTnet connection. If you’re thinking of investing in fast, reliable internet access you can make that investment go further by taking BT SIP Trunk and replacing your existing phone lines.

You’ll also need a phone system. BT SIP Trunk works seamlessly with BT IP phone systems, so if you’re buying a new phone system you should consider BT SIP Trunk as an alternative to traditional phone lines. Not only can the cost savings help you maximise your investment, it can also help you make the most of the IP productivity and functionality features of the new phone system.

But if you don’t have a BT IP phone system or you have an older, traditional on-premise phone system you can still have BT SIP Trunk by using our BT SIP Trunk Gateway. This piece of equipment allows the BT SIP Trunk service to work with your existing phone system, giving you all the benefits of BT SIP Trunk without needing to invest in a new phone system.

SIP trunking in a nutshell

SIP Trunk phone systems allows larger businesses to manage all their telephone calls over a single data connection.

It keeps costs down because calls are generally cheaper, and you can use your existing phone system and handsets. Plus it allows you to have multiple phone numbers without the need for multiple phone lines.

If your business is growing, it’s easy to scale your phone system. And if you need to move premises, you don’t need to change your phone numbers because they aren’t tied to the local exchange.


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