Save up to 30% on your line rentals by moving to SIP

Times, they are a changin'

SIP trunking is a future forward 

BT have announced that their ISDN will eventually be switched off by 2025, starting in 2020! But what does that mean, and is your company ready for the change?

ISDN stands for the Integrated Services Digital Network and comes in two flavours: ISDN2 and ISDN30 which each allow for 2 and 30 channels per line respectively. The switch-off means that business using these services will no longer be able to do so.

What do BT have planned for the 3 million channels that are still running through the ISDN?

The plan is to move them onto a technology that for some is brand new and for others is as old as you can remember: VoIP.

Voice Over Internet Protocol is the umbrella term for any voice channel travelling over the internet, and is much more flexible than the ISDN, believe it or not it has been around since the turn of the millennium.

Are there any actual benefits to using VoIP over the ISDN?

In a word: YES. 

Flexibility - In an ISDN setup, only the phones that are in your building are able to access your business's number, meaning that if for whatever reason an employee can't make it to the office through illness - or usually weather then to make contact with your customers they will have to use their mobile or personal landline. In a VoIP setup, you can give your employees a phone to keep at home for such an occasion and have it log in to your phone system as if it was any other phone on the network. Your employee keeps their extension number and even more besides, and it won't cost them or you an extra penny. Another alternative is using a softphone - an app that can be downloaded onto most mobiles or computers and used again as if it were an extension on your phone system.


Freedom of location - As long as you can access the internet, you can access VoIP. Furthermore you can get a number that presents itself to be in any location. Also available are the designated non-geographic 03 numbers! You can also have multiple branches all over the UK and even the World, and your Japanese team can talk with your Italian team using extensions as if they're just in the next office.


Disaster recovery - If your ISDN lines go down, your phones are down, and there's no telling how long it could take for your system to be back up and running. If you have no lines, you have no phones and that is that. With VoIP your lines are virtual, and can be carried over any internet connection, be it ADSL, leased line, wireless P2P or 4G, meaning you can instantly fail-over to any other means of connection should your main internet access go down, leaving your phone lines unaffected.

Lower costs - An important consideration for any business is call costs, and a VoIP service can not only slash your line rental costs, but save you money on things like calls to mobiles and international calls. You can also make internal calls for free no matter where someone physically is, as long as they have a connection to the internet in their office or on their soft-phone - especially useful if you have a fleet of mobile workers.

Expandability - With ISDN30 if you want to be able to have more than 30 channels, you're a call centre for example and have just taken on your 31st agent, then you have to ask your supplier (probably BT) for a new line to be installed and wait however many weeks and months for it to happen. They have to dig up roads and pavements in the process and the rental on a new line does not come cheap. With VoIP you have as many channels as your bandwidth can handle - you can get calculators online for this sort of thing, but the important number if doing a speed test is your upload speed. Looking the other way if you have an ISDN30 line but only 20 employees then you're paying for 10 channels you will never use, with a VoIP system you pay for what you use, from a single self-employed trader to a multinational corporation with over 10,000 employees.

So why wait?

With all these advantages of VoIP over ISDN, you may be wondering why you should wait until 2025 to move your systems over. The simple answer to that is: you shouldn't. Talk to us today!!

There were 1.9 million SIP Trunks in the UK by the end of 2015


Source: The Voice of VoIP Jan 16

SIP Trunking for your business

Benefits to SIP trunking:

  • Save up to 50% in line rentals and up to 25% in call charges

  • Free internal call access

  • High-quality voice and data services through a single connection

  • Potential to save money and maintain quality of service

  • Keep the same number when re locating offices and avoiding call forwarding costs

  • Greater control allowing you to decide how and where calls are delivered

  • Full scalability - scale the number of lines up or down to suit their business needs

  • Rationalise your ISDN lines and reduce the number of PBXs needed

  • Host your PBXs in the cloud saving space and enhancing security

  • Use your existing broadband or ethernet connection to upgrade to SIP easily

  • Greater resilience and security to ensure business continuity in the event of a disaster

Moving office?

Number flexibility with SIP trunking offers a way to maintain your current number easily, even when moving out of the area. Saving you the cost of changing company print, websites, stationery and telling your customers whilst maintaining the perception that you still have a presence in the area you’ve moved from.

Need to improve your data connection?

As a company ask yourself one question;


What would happen if you can't connect to the internet?

Businesses rely on connectivity make sure yours is up to the job.

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Hacking and abuse of business telephony is becoming as big as credit card fraud. With this type of abuse, the cost of the calls falls to your business.