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Your SIP Trunk Provider

In an increasingly connected world it’s important to be at the forefront of technology. SIP trunking solutions are the most cost-effective and efficient way to communicate with customers, clients and businesses. If you’re a thriving start-up or an established corporation, Fuse2 can pave the way in efficient communication through high quality SIP Trunking, enabling your business to stay connected with the world and communicate seamlessly.

We can take your business communication to the next level by setting up a SIP trunk and converting your existing telephone line to a modern IP-enabled connection, including ISDN conversions. This will give you access to a wide range of new features and advantages, from cheaper calls and greater reliability to additional software tools and network control options.

No matter what your company requires from its SIP trunks, Fuse 2 has the expertise and experience to help your organisation create a system that is cost-effective, highly secure and individually tailored. As an award-winning provider of premium communications solutions, we can deliver a fully comprehensive service, supported by an enterprise-grade network.

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Our SIP Trunk Solution

We can help your business install top-of-the-range SIP trunk solutions through a complete end-to-end service, dedicated to providing you with the very best call quality, network performance and ease of management.

Our SIP trunk solution include:

  • Setting up a brand new SIP trunk network for your organisation, or converting a previous ISDN setup over to SIP trunks
  • Helping you port your existing phone numbers over to the new network
  • Integrating your new SIP trunk setup with communication software and tools such as Microsoft Teams and Cloud 3CX
  • Introducing you to the many features offered by your upgraded connection, from voice, video and messaging applications to desktop sharing, web conferencing and shared whiteboards
  • Providing ongoing network management support to ensure stable, reliable and high-quality call services

No matter what your needs may be, we can work with you to create a bespoke SIP trunks setup that meets all of your requirements, in terms of technical performance and functionality, while also ensuring your business is able to take full advantage of the new software tools and network capabilities available to you.

What is SIP Trunking?

SIP (session initiation protocol) trunking is an innovative form of telephony that connects your company’s phones to the public PSTN telephone network via internet-based data transfer and VoIP (voice over internet protocol), rather than through the traditional phone lines.

With SIP Trunking this means your phone services are no longer tied to any local exchange, meaning you can choose phone numbers without being linked to any specific region, as well as avoiding conventional calling charges. Data-based calls also offer a better sound quality, easier call recording and more seamless integration alongside systems like Microsoft Teams.

SIP trunks are a direct successor to older ISDN lines, with an increasing number of businesses shifting from ISDN to SIP trunk-based telephony in recent years.

helping with sip trunking

International SIP Trunking Providers

We understand the importance of efficient communication in today’s global business landscape. Our SIP trunking services provide businesses of all sizes to establish reliable voice connections across borders, without the constraints of traditional phone lines or ISDN lines as you may know them.We can provide you with a brand new SIP trunk in 40+ countries with a seamless transition period.

SIP Trunking Solution Benefits

By switching to SIP trunks for your business, you can unlock a host of advantages that range from substantial cost savings to enhanced flexibility and advanced communication features.

Enjoy many IP features

Converting to SIP trunk enables your legacy phone systems to benefit from a whole host of modern IP features, including:

  • Enhanced functionality, including improved support for video messaging, conference calls and media sharing
  • Call recording provided via SIP, rather than at at private branch exchange (PBX) level
  • Create new fixed-line numbers for your business with local area codes, rather than being limited by your geographical location
  • Reduced costs on lines coming into the business when numbers are ported

Save multiple costs

With a suitable internet connection – whether supplied and managed by Fuse 2 or an existing solution – SIP trunks enable business voice calls to be routed through the internet via the Fuse 2 carrier-grade network, delivering competitive call rates, even for international calls.

For legacy systems that do not allow VoIP, Fuse 2 can install and manage ISDN conversion units that convert analogue calls to SIP, without affecting any aspect of the existing system. This eliminates unnecessary expenses such as hardware purchases, installation and maintenance costs.

Future-proof your phone setup

The traditional ISDN phone network is set to be turned off entirely in the next few years, with an expected date of 2025 set in the UK. By converting to a modern voice solution now, you will be protecting any future investments you make within your communication network, and ensure you will be ready for the future of business communications.

How can fuse2 help with your SIP Trunking?

We deliver the highest quality of SIP Trunk solution for your business. As an award-winning independent provider of communication services for organisations all over the world, and can work flexibly to find the very best solution for you.

as your trusted SIP trunk provider, we will unlock your world of communication.

Fully managed end-to-end service

You can work with a single trusted provider over all aspects of network usage, accessibility, security and monitoring

Enterprise-grade network

We proactively monitor via sophisticated bespoke software providing us with clear performance metrics for your peace of mind.

Guaranteed Call Quality

A highly diverse carrier network that allows us to guarantee call quality and each segment of our voice platform to operate regardless of interconnect outages

Transparent oversight

Oversight on all equipment, with notifications sent to engineers to ensure the end user is notified of potential disruptions or issues before they have even been noticed

Who needs a SIP Trunking?

SIP trunking services cater to Small and medium-sized businesses benefit from its cost-effectiveness, while large enterprises find scalability and centralised management. 

Call centres rely on SIP trunking for efficient operations, and international businesses value its ability to provide local phone numbers worldwide. With the rise of remote work, SIP trunking supports flexible work arrangements, while companies with high call volumes or seasonal demand benefit from its scalability.

Talk to the SIP Trunk Solution Experts

Setup your SIP Trunk Today

We’re a fully independent company that provides the same quality of service as a big brand, meaning you will always receive friendly and personalised customer service from us, with a focus on custom network solutions tailored to your specific needs.

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SIP Trunk Solution FAQs

What’s the difference between SIP and VoIP?

SIP (Session Initiation Protocol) and VoIP (Voice over Internet Protocol) are related and are often used together in modern communication systems, but they both serve unique purposes. Here are the key differences between SIP and VoIP

VoIP (Voice over Internet Protocol):
Broad technology for transmitting voice, video, and communication over the internet.
Encompasses a range of protocols, including SIP.
Used for various communication services like voice calls, video conferencing, and messaging.
Examples: Skype, WhatsApp.

SIP (Session Initiation Protocol):
Specific signalling protocol for initiating, controlling, and terminating communication sessions in IP networks.
A subset of VoIP, focusing on session setup and control.
Primarily used for voice calls, video conferencing, and real-time communication.
Example: Used to establish and control calls, while VoIP handles actual data transmission.

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

There is no limit on the number of phone lines with SIP trunks, making it highly scalable for businesses of all sizes.

How many concurrent calls can a sip trunk handle 

The number of concurrent calls a SIP trunk can handle depends on several factors, including the capacity of the SIP trunk, your network infrastructure, and your service provider’s offerings. Contact our expert SIP Trunk team for more information on your SIP requirements.

Why do i need a SIP trunk

SIP trunks are a cost-effective alternative to traditional phone lines, offering substantial savings on long-distance and international calls. They provide scalability, allowing you to easily adjust the number of concurrent calls to match your business’s growing communication needs.

SIP Trunks promote business continuity with features like disaster recovery, ensuring your operations remain accessible even during network disruptions. We help modern businesses with streamline communication, reducing costs, and improving overall efficiency.

How do SIP Trunks Work

SIP trunks, or Session Initiation Protocol trunks are the backbone of modern business communication systems by facilitating VoIP and multimedia services over the internet. When a call is initiated, SIP trunks create a virtual “session” and use SIP signalling to establish a connection between your caller and you.

 This signalling involves the exchange of SIP messages, like requests and responses, to initiate, maintain, and terminate the session. SIP also handles multimedia session descriptions and parameter negotiations during setup, such as choosing codecs and encryption. Throughout the call, SIP remains active, controlling features like call forwarding and monitoring the session. 

As the call concludes, SIP signalling is used to gracefully terminate the session, ensuring that resources are freed up for future calls. Call Detail Records (CDRs) are often kept for billing and analysing performance of networks as you develop your business you may need to upgrade in the future.

SIP Trunk Example

Lets use a hypothetical example of Company ‘A’

Company ‘A’, with offices in the US, Europe, and Asia, wants to improve communication and reduce costs.

They partner with Fuse 2, a global SIP trunking provider. Using virtual numbers, we establish local presence in each region. Calls route through SIP to PSTN seamlessly, saving costs. With failover options and 24/7 support, they enjoy reliable, efficient communication.

Company ‘A’ achieves streamlined, cost-effective communication across international offices, boosting productivity and collaboration and reducing costs calling internationally.


In addition to our vast experience and expertise, our customers enjoy our personal approach to our work. We tailor our services to suit their individual requirements, and offer the highest levels of communication throughout our working relationship.


Certified Ribbon Service Provider & Microsoft Partner.


24/7 Support & Monitoring with UK Engineering Teams.

Points of Presence

Independent Carrier Network with Global Points of Presence.

Extra Functionality

Additional Call Control & Features not present with Microsoft.

Award Winners

ITSPA Award winners in multiple categories.


Channel based calls pricing rather than per user.

To find out more about SIP Trunks Arrange a two-week, no-obligation proof of concept, get in touch with our team of experts today. Arrange a call back at your convenience.

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Fuse 2 are now the official range holder of all iHub numbers. If you have any information regarding legacy iHub services please get in touch +44 330 088 0333