BT Shutdown PSTN & ISDN

BT to discontinue analogue PSTN

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BT to discontinue analogue PSTN

The reliance on PSTN (Public Switched Telephone Network) as a form of alarm signalling is almost over.

When Will BT Switch Off The Telephone Network?

  • BT aim to have converted 3 million homes by 2020.
  • Complete shutdown of the PSTN network by 2025.

Now that BT have announced the migration to All IP, and the switch off of PSTN in 2025 we must accept that the change is happening now, although voluntarily at first. BT, amongst all the other major carriers, are encouraging the move to high speed broadband as fast as they can. It is a situation that has been coming for some time, but now this is “official” and for the security Industry it is time to consider the implications.

Old System Obselete

BT to switch off analogue telephone system by 2025

The older copper-based services are becoming so obsolete that parts are becoming harder to source. Also the people with expertise in these older systems are retiring. The economics of maintaining these older networks is now taking over and they simply have to be replaced.

However, BT have no plans to remove the physical copper and that some copper services will continue to work (e.g. Redcare Classic & GSM, which are independent of the PSTN). Delivery of new services will be over a mixture of copper and fibre depending on location.

The main push was from 2018, and BT will want to convert as many as possible as quickly as possible. The roll out will only accelerate.

PSTN Systems

The real issue for the security industry is that there is a vast amount of PSTN based alarm signalling devices in circulation.

Many of these are using diallers that are no longer manufactured or supported.

The common issue reported from the security industry from changes to All IP is that some PSTN devices will begin to have intermittent signalling problems, some will not work at all.

Clear Message

The message must be clear. The reliance on PSTN as a form of telecommunications for alarm signalling is almost over. The rapidly changing infrastructure in the UK means that PSTN devices installed in good faith today, may not operate correctly tomorrow. Specifiers, Installers and all interested stakeholders must avoid installing PSTN based equipment and look to alternate technologies now.

What are the options post PSTN?

BT to switch off analogue PSTN telephone system by 2025

For over 40 years PSTN in the form of digital communicators has been the cheap go to product for low risk security, fire and other remote signalling systems.

However, now that BT has announced that ALL IP will be their method of delivering communications into premises then we need to look at the alternatives on offer.

All the major communication system manufacturers are gearing up for the demise of the digital communicator and the options are polarising around either radio or IP systems. So what is going to replace the Digicom?


Radio is probably the easiest replacement but it is dependent on there being a strong enough radio signal available to ensure a reliable communications path. Most engineers are familiar with setting up radio systems so the transition to radio would be an easy option. The power requirements for radio comply with the current standard, using the panel or ancillary power.


IP is becoming more widespread and connecting to networks is becoming more mainstream with options of direct connection through Ethernet or indirect through powerline adapters or wifi. For IP, consideration must also be taken for providing a UPS to ensure the router still works during a power outage to ensure the signalling path conforms to the transmission standards.

We will inform of any further updates on this subject.

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