SIP Trunking

A reliable and secure way to
add external calling
to your phone system.

Call us to discuss your solution on 08009530180

Our sales team are available Mon – Fri, 9am - 5pm

Excluding bank holidays


What is SIP Trunking?


If you are looking to simplify your approach to telephony, SIP Trunking is a reliable, secure and cost-effective way to manage voice calls using the data network.

You can still use your existing on-premises phone system even after analogue lines are switched off in 2025, putting you in control about when to move to a cloud-based unified communications service in the future.

SIP trunking

How does SIP Trunking work?


SIP Trunking connects your phone system to our network using an IP connection, passing voice calls between your sites and the wider network.

We also provide access to a secure SIP Trunking Portal where you can configure call diverts, create business continuity plans and access detailed statistics and usage reports for both inbound and outbound calls.


What can SIP trunking do for your business?



You only need a connection to a single central site, so you don’t have to pay for lines and channels you don’t need.



Keep using your existing phone system even after analogue lines have been switched off by 2025, so you can transition to a centralised system in your own time.



You can keep existing telephone numbers and you can present different numbers for outbound calls too.



Scales the service up and down to meet your current needs, giving you flexibility in busier or quieter times



You’re in control and you can manage both inbound and outbound calls from the SIP Trunking Portal.  



We can provide our SIP Trunking service over any IP network. Choose from our data connectivity options or use your own internet service.


Talk to an expert now

No pushy sales stuff, honest. Just a whole lot of knowledge and advice from our specialist team.

Call us on 0808 159 5197

Open Mon - Fri, 9am - 5pm
Excluding bank holidays


Why work with us?


You’re at the centre

Our approach to SIP Trunking puts you at the centre, with a secure SIP Portal that gives you full control and visibility.  


Eliminate hassle

One provider for all your communication and connectivity needs, with seamless delivery when you need to make changes. 


Years of experience

We have many years of experience helping organisations manage their voice technology, so you’re in good hands.


SIP Trunking FAQs


What is a SIP channel?

A SIP channel is the capability to support incoming and outgoing calls. Every SIP trunk contains a number of channels, which act as virtual versions of telephone lines. The number of channels you need depends on how many concurrent calls your business makes.

What is the difference between SIP and VoIP?

VoIP or Voice Over Internet Protocol makes and receives phone calls over the internet or internal networks. SIP is an application layer protocol used to make and manage multimedia sessions, including voice, video and messaging. SIP is mainly used to support IP technology, like VoIP calls.

What is the difference between SIP and ISDN?

SIP Trunking is a newer technology and allows voice and data to be carried on the same channel. SIP Trunking uses the internet or a private network to deliver voice and data through a single line, whereas ISDN uses the traditional copper network to deliver voice and data.

What are the requirements for SIP Trunking?

To use SIP Trunking, you will need an internet or private connection, e.g. IPVPN, with good bandwidth and speed. You will also need a compatible SBC (Session Border Controller) and PBX (Private Branch Exchange).

Is there a limit on how many phone numbers I can have?

Not at all! You can have as many phone numbers from as many locations as you like.

What’s the difference between SIP Trunking and a hosted PBX?

SIP Trunking creates a virtual link between your existing PBX and the PSTN using an internet based, or private, connection. A hosted PBX brings you fully to the cloud and removes the need for on-premises infrastructure, this may be your preferred option if you are looking to replace your on-premises PBX.

Can I use SIP Trunking for international calls?

Yes, you can use SIP Trunking for international calls. However, you may incur additional charges for international calls.

Where can I learn more about SIP Trunking?

Learn more about our SIP Trunking solution with our Product Sheet


Contact our Enterprise and Public Sector sales team



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