TNBN SIP Trunks work with all onsite UK phone systems including 3CX services. We offer 99.99% reliability across multiple failover networks and provide free set up and UK based support.

call us on 0800 019 5562

Two low cost price plans to choose from

£4.50 per month with PAYG calls. (UK landline 2ppm and UK mobile, 02, Vodafone, Orange, Three & EE 5ppm / 2p set up fee per call)
£9.50 per month with 5000 bundled minutes (3000 UK landline and 2000 UK mobile 02, EE, Vodafone, Orange, per channel. Example 2 channels will give you 10,000 minutes).

Why TNBN SIP Trunks?


Over 5000 connections.


Over 300 UK schools.


99.99% reliability with fail over systems.


HD quality sound.


Scale lines up and down in seconds.


Route calls to alternative destinations in seconds.


Short term contracts.


Works with all major phone systems including 3CX.

Let’s place your order – If you require any help or information please call us on freephone 0800 019 5562 Monday – Friday 9am – 5pm.

Your set up is easy.

1. Complete the form below
2. We shall email you a direct debit mandate for you to complete and return
3. Once received we shall set up your account and email you the SIP configuration details.

Some Of TNBN’s Happy clients.

Book an appointment to discuss TNBN SIP Trunks in detail.

TNBN Information on SIP Trunks

What is happening & why do I require a new phone system?

Openreach have announced that they will no longer support existing traditional analogue multi-line, ISDN2 or ISDN30 channels by 2020 and will be switching the network off entirely by 2025. The UK is to switch to a single IP network delivering faster, clearer and more cost effective communications. Please Click here to read the Openreach statement regarding withdrawal of service.

Why is this happening?

Today’s business climate calls for reliability, agility and flexibility. In order to deliver on these core goals, the tools companies need to communicate to their customers and the wider world must be future ready and fit for purpose. However, that is not always the case and most companies are still relying on traditional phone lines or ISDN technology for communications, most of which are now becoming obsolete in a business environment where terms of interaction are dictated by increasingly demanding customers. The UK’s current network relies heavily on physical infrastructure, specifically copper wiring, which takes up space within a business premises and requires resources to administer and maintain. Similarly, it is hard and costly to add new phone lines and requires physical addition and can take up-to 14 days to install. Physical ISDN or Multi-line monthly line rental costs are also expensive along with high call charges. The traditional phone network has no real security and phone systems can easily be hacked undetected for dial through fraud and can cost a customer thousands in unwanted bills. Faults on the current network can take days to fix and with noisy lines and dead tones the current network is simply out of date.

What is the replacement?

The future ready replacement is SIP Trunking. SIP is a ready made replacement for traditional multi-lines and ISDN, connecting a business phone system to the IP network via broadband, ethernet or a private circuit. SIP Trunking works through data centres rather than the local exchange so there is no physical connection meaning less space taken up and less to maintain. As there is no physical connection you can scale lines up and down in minutes by calling your service provider. SIP Trunks are inexpensive to run with call costs at a fraction of the price of traditional phone rates. The IP network has multiple layers of security and TNBN can set provisions on call spend to automatically detect dial through fraud. The IP network works on HD sound quality and is 99.99% resilient with back up data centres for disaster recovery. Should a fault occur you can re-route calls to an available landline or mobile within seconds offering better continuity of service.

What do I need to switch onto IP

You will require a good broadband connection (fibre, ethernet or a private circuit) which will hold a number of phone calls at any one time, an IP onsite or cloud based phone system.

Are my phone services at risk if I don’t switch to IP?

Yes, you are required to make the switch or you risk losing your phone service if it is no longer supported or it has been switched off by Openreach. There are currently over 2 million traditional multi lines & ISDN services in place so it’s best to make the switch sooner rather than later to avoid any disappointment.

Can we keep our same phone number?

Yes, TNBN has a porting system that allows us to transfer your current phone number to the IP network.

Do I need to be involved in the switch over to IP?

No, TNBN offers a fully managed switching process from start to finish.


As the budget belt is being tightened, and costs for telecommunications are on the rise, TNBN is your number one choice based on our high service levels, low rates and never having a single complaint filed against us with OFCOM since we have been in operation. We work alongside a combination of main stream providers to ensure a smooth transition from traditional phone service to IP.