There is growing awareness that the PSTN telecom network is to cease operation by the end of 2025, with all users moved to IP-based services, according to BT. This will impact users with responsibility for security and fire alarms who will need to start planning to ensure that installed systems continue to operate after that date.

According to industry sources, nearly 3 million intruder alarms installed in commercial and residential premises still use PSTN. In addition, around 1.7 million vulnerable people rely on PSTN connected telecare systems in the UK. With broadband take-up in households and non-domestic sites of over 90%, the momentum is clearly moving toward consolidation on IP, whether wireless or fixed line. At the same time, whole or parts of existing analogue networks are being replaced or upgraded with the corresponding Next Generation Networks (NGN) components to deliver higher speeds and improved quality of service while attempting to maintain legacy services provided by the original network.

There are pressing issues affecting security and safety alarm signalling that need to be addressed immediately. There is an increasing number of signalling failures resulting from the migration from traditional circuit-switched networks (PSTN/ISDN) to NGN with an all-IP platform (IP multimedia sub-system with softswitches). Because round trip time delays can be added over an NGN, signals may never be received at the alarm receiving centre, often without warning. The problem only becomes evident when signals fail to arrive, resulting in protracted investigations involving all parties until the issue is finally isolated and identified – Bold is frequently called upon to troubleshoot on these occasions.

This will be the end

Whilst problems arising from round trip delays may be intermittent, there is no doubt about when the PSTN network will be switched off. When it happens, devices that rely on PSTN communications will not work. Communications providers are considering offering short-term solutions, such as analogue to IP convertors, but this is unlikely to resolve issues such as round trip time delays, line powering or back-up power.

Networks based on ‘Voice over Broadband’ (VoBB) or ‘derived voice’ will not necessarily support services that rely on conventional end-to-end ‘PSTN’ delivery. For example, DTMF tone transfer issues are already being experienced with VoIP networks causing some security and care alarms to malfunction. This may also extend to other security applications and will need extensive service re-engineering and the potential installation of new equipment on customer premises.

Looking forward, whilst manufacturers will move to a fully digital IP-based approach, it is important to consider that the new technology will also not have the line powering capability of the PSTN. What this means for security, telecare and other non-voice services is that alternative power arrangements will have to be provided. Further consideration must be given to the fact that fibre-based broadband may not be available in all areas and it does not always provide high levels of resilience. This means that any local mains power failure will cause loss of service unless supported by UPS devices or battery back-ups.

Bandwidth is also an issue as broadband connections typically support multiple services. To ensure that “safety of life” services work effectively, prioritisation needs to be applied for the relevant data traffic. Layers of protection must be deployed to protect against cyber-attacks that cause device or service failures or the appropriation of devices for malevolent purposes.

In the meantime..

Before the PSTN network is switched off, users need to be aware that simply changing communications provider is not always the answer. This is because what works on one NGN network is not guaranteed to work on another and problems often arise when switching to a new provider.

There are other issues that are already occurring as a result of changes being made during the shift to IP-based technologies. The gateway devices used to interconnect the legacy networks to the new IP elements are interfering with the handshaking process causing potential delay and signal failure.

Meeting NGN Requirements

An alternative mechanism for alarm signalling before 2025 must be found. Signalling over PSTN networks, while not being the most secure or highly featured option, has been a reliable way to communicate low priority alarms. Most users requiring more secure and resilient signalling have already changed and it is now only the ‘late adopters’ who must find an alternative to systems which have suddenly and unaccountably become unreliable.

Manufacturers such as Bold Communications are already ahead in the efforts to deliver cost effective solutions that meet the demands of this changing environment and which support a seamless migration from legacy analogue to NGN signalling. With over 35 years’ experience of the UK alarm handling sector, supporting both commercial alarm receiving centres and private monitoring control rooms, Bold can deploy alarm communications solutions which meet the full range of users’ needs. The company also provides 24/7 technical resources to deal with alarm signalling issues.

There are comprehensive signalling solutions available today that not only meet the different needs of users, but also fit NGN infrastructures. Options include Grade 2 single path devices and up to Grade 4 with multiple path signalling, including IP, mobile data and GSM. The mobile option is becoming increasingly attractive as reliability and coverage have improved in line with ongoing reductions in airtime tariffs.

Wired internet connections used for the main reporting channel enable fast and reliable alarm transmission and action without adding to ongoing operational costs. The secondary reporting channel can be wireless using the mobile data network and provides either dual-path reporting or backup in the event of a failure to the ethernet network. It can also serve as the main signalling channel if there is no ethernet network at the site. Configurable polling quickly reports loss of connection and AES encryption ensures highly secure monitoring.

In conclusion, the security, fire and telecare sectors should not to wait until problems occur or leave it until the PSTN telecoms network is switched off before taking steps. There are solutions available now that will ensure that installed systems continue to operate efficiently and provide ongoing protection for users.

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