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SIP Trunking

With SIP trunking, your business can operate its own on-site IP PBX system. Xinix has been offering our own SIP trunk solutions for over 10 years.

Enjoy benefits from cheaper business calls and greater flexibility. We are an expert SIP Trunk provider, our knowledgeable engineers will be able to help with all your SIP Trunk needs, including any questions you might have in the first instance.

Select your package


£ 4 / month
1 SIP Line Included
Add More SIP Lines
Minimum 1 channels required
Add Phone Numbers
  • Quick activation
  • Multi-node network redundancy
  • 30 Day rolling term

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£ 12 / month
1 SIP Line Included
Add More SIP Lines
Minimum 1 channels required
Add Phone Numbers
  • 1000 Landline & mobile UK minutes per SIP line
  • 30 Day rolling term

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£ 19 / month
1 SIP Line Included
Add More SIP Lines
Minimum 1 channels required
Add Phone Numbers
  • 3000 Landline & mobile UK minutes per SIP line
  • 30 Day rolling term

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£ 24 / month
1 SIP Line Included
Add More SIP Lines
Minimum 1 channels required
Add Phone Numbers
  • 5000 Landline & mobile UK minutes per SIP line
  • 30 Day rolling term

Find out more

99.999% Guaranteed Uptime

No Long-Term Contracts

Real Time Online Billing

Up to 84% Cheaper than ISDN Lines

Multi-Node Network Redundancy

Low International Call Rates

SIP Trunks for your on premise PBX

Business SIP Trunking

Business SIP trunking is a service that enables your company to operate a selection of telecommunications systems over your IP network. It offers a number of benefits - from cheaper international call costs to improved business flexibility. Incorporating a Disaster Recovery strategy to give access to an increased quantity of numbers, business SIP trunking from Xinix World can enhance the way your business stays connected.

Our business SIP trunks represent the latest in telecommunications technology. They are a more affordable alternative to ISDN30 line rental and internet services while retaining a level of performance that is high in flexibility and can be tailored to your own specific needs.

In addition, we provide a managed service to cover IP connectivity and number management, ensuring that business SIP trunks from Xinix World deliver a complete communications solution.

Visit our information page on — What is Onsite PBX?

We are a vastly experienced SIP trunk provider, so our knowledgeable engineers will be able to help with all your SIP Trunk needs, including any questions you might have in the first instance.

Call Rates

UK Rates

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Peak: Mon-Fri 8am - 6pm
Off Peak: all other times
Weekend: midnight Friday to midnight Sunday

International Rates

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International charging categories listed as ‘Special’ include non-geographic numbers in that country;
Xinix, however, does not guarantee to provide connection to all non-geographic numbers.
A connection fee may apply in some countries.

Why XINIX World SIP Trunks?

We operate our own core network infrastructure to support SIP trunk services.

We can provide telephone numbers from areas throughout the UK, routing them through to a single office location.

We deliver compatibility with a wide range of SIP devices from a number of manufacturers.

We supply a full array of components to connect your system via SIP trunks, taking responsibility for delivering your service from the day you order.

Cost comparison

Number of Lines/Trunks BT ISDN 30 Xinix SIP Trunks Saving
BT ISDN30e with 10 channels £264.00/ month £20.00/ month £1928/ per year (92%)
BT ISDN30e with 30 channels £792.00/ month £60.00/ month £8784/ per year (92%)

SIP Trunking vs ISDN

  SIP Trunking ISDN
Circuits/Hardware All connections are virtual, limited only by bandwidth available. Session Border Controllers (SBC) may be required for security and come at an additional cost. All connections are physical, requiring manual connectivity and expensive termination hardware.
Scale/Growth Easily scalable, a quick software configuration can add new channels and can offer automatic and on-demand burst capabilities. Growing the network requires the installation of new circuits and additional hardware. For PRI, the increment is 23 voice channels.
Backup/Redundancy Automatic IP re-routing enables the distribution of PSTN connectivity to sites with limited or network redundancy. It can also be designed to retain PSTN reach in the event of hardware loss. The provision of backup circuits to remote sites in an IPT-distributed architecture can negatively impact ROI. The only way to accommodate hardware loss is to structure excess capacity with associated costs.
Cost Various pricing models – such as on-demand – are available, with the cost significantly lower in comparison to PRI circuits. The cost of PRI is typically on a per circuit, per month basis, with an increase in voice channel requirements available in fixed increments.
Capacity Planning While lead time is always important, extra capacity can often be added with a simple software upgrade. In addition, it is often possible for providers to accommodate temporary burst capabilities for periods of increased activity. Due to the need to arrange installation of circuits and termination hardware, any additional capacity requirements must be planned well in advance.
Disaster Recovery / Business Continuity Automatic call re-routing to pre-defined locations is simple, quick and affordable. Plus, SIP trunking is capable of accommodating diversity across service providers. Diverting calls to alternative locations can be complex and expensive.

Benefits of SIP Trunking

Cost saving

Thanks to multi-modal communication capability, SIP trunking enables you to save more that 30% on monthly telecommunications costs.

Trunk aggregation

By centralising and eliminating redundant connections, you are able to use idle connections in one location for calls at another, thereby offering increased flexibility over traditional PRI circuits.


Depending on the needs of your organisation, the ability to add or reduce connection capacity is simple, thereby increasing the flexibility of the service you provide.


By keeping communications data on pure IP connections as opposed to T1 PRI connections, SIP trunking offers improved voice and video quality, delivering almost HD-like audio.

Simplified billing

By aggregating all the voice and data services into one product, you can take advantage of reduced administration with simplified billing.

Don't just take our word for how good we are

Reliable UK SIP Trunking

  • Save on business calls
  • Cheaper alternative to ISDN30e solutions
  • More minutes for less
  • Guaranteed call quality
  • Retain your existing telephone numbers
  • Perfect for all Disaster Recovery requirements
Selecting Data Circuits

If high-quality calls are a requirement for your business, it's important you support your network with the right data circuits. Standard ADSL is ill-equipped for the delivery of voice data, not least when a congested network can cause significant disruption to your calls. Instead, we recommend investing in either an Ethernet circuit, whose stability can accommodate a number of simultaneous calls, SDSL, SDSLM, or Voice-Approved ADSL.
Simply contact Xinix today to discuss the best option for your business.

SIP Trunking Explained

Session Initiation Protocol – or SIP – is a signaling communications protocol commonly used by internet telephony service providers (ITSP) to deliver voice and video calls over IP networks. It both establishes and closes calls over a network, and works alongside other protocols in transporting thousands of data packets containing audio and video information. Unlike such services as Skype, business SIP trunks provide ISDN30e quality – far superior in terms of performance and stability.

The Numbers You Need

One of the main advantages of choosing business SIP trunking from Xinix lies in the ability to have numbers from the dialing codes you want to be delivered directly to your office, regardless of location. The ability to centralised numbers from such diverse places as London, Manchester, Birmingham, and Glasgow to a single hub ensures that establishing a nationwide presence for your company is simple. Just specify the dialing codes you desire, and leave us to do the rest.

Disaster Recovery

Telephony downtime can damage both the finances and reputation of your business. With Session Initiation Protocol (SIP), there is a Disaster Recovery strategy ready to support you should the worst happen.
The first level of resilience in SIP trunking Disaster Recovery is the ability to reroute calls to a backup IP address and/or location. The second level is the ability to divert calls to backup ISDN30e or local telephone numbers on a Direct Dial In (DDI) to DDI basis. With such means of resilience available, there is no reason for users to even be aware of any issues.
You can discuss your Disaster Recovery options with our engineers today. They will be happy to talk you through the full selection of available services.

Quality Assured

This improved quality is assured thanks to the manner of delivery; each IP data packet arrives in the correct order and without delay, one after the other. Thanks to SIP trunking services from Xinix, this steady stream of delivery means that packet loss, time delays, and interruptions in delivery are never experienced. But how do we achieve this?

If you’ve ever experienced delays or problems in communication over IP, the most common issue stems from your internet service provider being unable to guarantee that your data will be forwarded onto your ITSP without delays. Instead, it’s often the case that your data will pass through some networks before finally reaching your ITSP, with a corresponding deterioration in quality.

With XINIXWORLD, there are no such issues. As a provider of all the services needed for successful communication, there is no delay and no compromising in quality. Our SIP trunking services ensure the same ISDN30e call quality, along with the ease and value for money to keep your business at the forefront of telecommunications.