ISDN Phaseout 2020: How Can Your Business Cope?

24th November 2020

BT announced the end of ISDN back in 2015. The telecommunications service provider said that it would stop taking new ISDN orders in 2023 to altogether deactivate its ISDN network by 2025.

BT acknowledges that the nature of telecommunications has changed drastically in the past decade. ISDN networks can’t support the level of communications that companies need today. Thus, the company has decided to stop investing any more time and money into a technology that can’t help the business world grow.

By switching off its ISDN networks, BT is forcing businesses to migrate to better telecommunications networks that support their growth.

With ISDN’s days numbered, the question is: Is your business ready?

What does the ISDN phaseout mean for businesses?How Does the ISDN Phaseout Affect Business

ISDN operates via standard phone lines and is mostly used for voice calls and data transfers. Since the network relies heavily on physical infrastructure, ISDN can be expensive to implement. It’s also tricky to install and upgrade since the networks need to be tied to local area numbers.

Considering the cost of maintaining ISDN networks, the phase out can be beneficial for your business. Switching to another telecommunications technology will reduce your operating expenses, increase your scalability, and support your growth.

Don’t wait for 2023 before migrating your phone networks. Start exploring your alternatives as early as now to find the phone system that’s best for your organisation.

The two most-used business phone systems today are SIP and VoIP.


Both Session Initiation Protocol (SIP) and Voice over Internet Protocol (VoIP) refer to internet telephony, but they can’t be directly compared. VoIP is a general term for any internet-based phone service, whereas SIP is one of the specific protocols that enable VoIP.

In short, VoIP refers to a type of voice transmission, and SIP is the protocol used to set up those calls. SIP is often used to enhance VoIP systems. So, a more valid question would be: how does VoIP stack up to VoIP with SIP?

But before we get into that, let’s first dive into the basic capabilities of VoIP.

What is VoIP?

Unlike ISDN that uses standard phone lines, VoIP phone systems rely on data connectivity to transmit voice signals digitally. VoIP is also referred to as internet telephony, IP telephony, or voice over broadband.

By using the internet, VoIP gives you the following benefits:

  • Portable and scalable communications, since you don’t need on-site installation
  • Predictable, flat-rate monthly billing
  • Low initial investment costs
  • Many basic VoIP service plans offer additional benefits, including caller ID, call forwarding and call waiting
  • Most VoIP providers offer flexible and customisable service plans, so you don’t have to commit to a long-term service contract

These benefits already provide much value to your business. But you can upgrade your VoIP phone system through SIP to unlock even more capabilities and productivity tools. A SIP-enabled VOIP system includes multimedia features, instead of just voice communications.

VoIP with SIP

Here’s how SIP can enhance your VoIP phone system:

  • Allows video conferencing, instant messaging, media distribution and other applications
  • Includes user-friendly administrative tools that allow you to add lines and features easily
  • Can seamlessly integrate with cloud applications, resulting in unified communications
  • May include built-in integration with typical business applications, such as CRM and other productivity software
  • Provides pricing flexibility by letting you choose the features and lines you want
  • Provides failover for your employees, in case of unreliable internet connectivity

Of course, VoIP and VoIP with SIP also have their disadvantages. But the biggest drawback to using internet-based phone systems is the bandwidth requirement. You need a strong, reliable internet connection that can support a high quality of service. Otherwise, your call quality might plummet.

If the internet connection is a struggle for your business, there’s another telecommunications solution you can consider: call answering service.

Benefits of Call Answering Services

Hiring telephone answering services is like having your own call centre. But instead of hiring dozens of employees and building a telephony network, you only have to pay the service provider for answering your calls. You may choose to have the calls transferred to your line or have them email the message.

Most telephone answering services are customisable. You can either let them take all your calls or only during certain circumstances, like when your office is closed or when you’re understaffed. Other businesses use answering services to make sure they never miss any calls.

This kind of service model is beneficial for small and medium businesses because it allows you to stick to your budget, no matter how small or big. In 2019, call answering services cost £14.99 to £84.99 per month, depending on your contract.

Planet Numbers offers reliable telephone answering services, ranging from £49.99 to £159.99 monthly. Our packages guarantee zero missed calls from the UK, up to 150 included calls per month and a 14-day free trial.

We provide businesses with a range of phone system solutions. From VoIP phone systems, call answering services and affordable international calls, we help you find a cost-effective solution that satisfies your business needs.

To learn more about internet-based phone systems or call answering services, call us on 0345 077 7777 or send us an email at