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What your business needs to know about telephony changes

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Old vs. New: What your business needs to know about telephony changes


"PSTN is a very old technology that operates on similar principles to the late nineteenth century’s first public phone networks."

Significant changes in the telephony sector are imminent, with digital technologies set to replace older systems, bringing a plethora of benefits.

Telecoms giant BT Wholesale has announced that customers will no longer be able to purchase Integrated Services Digital Network (ISDN) and Public Switched Telephone Network (PSTN) circuits from 2020.

The change paves the way for the modern alternative of Voice of Internet Protocol (VoIP). In this blog post, we outline the old technologies that are soon to be replaced, and provide a simple overview of VoIP and what it has to offer.

What are the old technologies?

PSTN is a very old technology that operates on similar principles to the late nineteenth century’s first public phone networks. This technology is still vastly used today, with most people having it at home, where analogue voice (and data via MODEM) flows over circuit-switched copper phone lines to the local telephone exchange.

ISDN on the other hand, enables both voice and data services to be delivered simultaneously over digital lines. When it was first rolled out in the late 1980s, ISDN was ideal for businesses, as it had the capacity to support early video-conferencing systems, whilst also functioning as an analogue phone line.

What is VoIP and how does it work?

VoIP - colloquially known as Internet telephony - is not a wholly new technology. It has been a proven platform for voice for some time. Put into lay terms, VoIP lets you make and receive calls – as with an ordinary office phone – but it uses the Internet, instead of the PSTN.

VoIP converts analogue voice signals to compressed digital signals that translate to Internet Protocol (IP) packets. These IP packets are then transmitted over the Internet and converted back to a regular analogue telephone signal, if the end user has a regular telephone.

What about its features?

VoIP offers a vast range of features, including:

  • Unlimited extensions
  • Voicemail (to phone and email)
  • Call recording
  • Digital Receptionist
  • Interactive voice response (digital receptionist function)
  • On hold music
  • Multi-site capabilities

What about the installation process?

Installing VoIP is very straightforward. If your business always has a high-speed Internet connection with adequate upload speeds of at least 2 Mbps, and an IP-based phone system, all that is needed is an adaptor to connect your Internet router to your main phone system.

If your current system is an entirely old circuit switched technology, it may be more beneficial to upgrade fully to a modern IP system.

What should businesses do?

While 2025 may seem a long way off, 2020 is just around the corner. Seeking advice from a telecoms specialist can help businesses to work out exactly what they do or don’t need to do, as the switch approaches. It is best to do this sooner rather than later. Ultimately, the changes are inevitable, so it makes sense to start reaping the benefits of contemporary telecoms now.


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Matthew Harvey
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