Maintaining connection to Emergency services during power failure

Maintaining a connection to Emergency services during mains power failure has been an intrinsic part of public telephone networks.

Most landline call services were delivered through copper wire connections over the ‘Public Switched Telephone Network‘ (PSTN). Traditional corded telephones on these lines could still be used to make calls during a power cut at the premises. That’s because the lines were powered and backed up by battery and/or generator emergency power at the local telephone exchange.

However, the UK’s traditional telephone network will undergo substantial changes in 2025. Providers will move away from services using copper wire and dial-tone, to relying on fibre broadband technology to carry [VoIP] phone calls as well as provide Internet.

Calls made through broadband using VoIP technology will not function during a power failure as the broadband equipment at your premises requires AC mains power to work. As a result, calls will only be possible if additional ‘protection’ measures are put in place.

Ensuring the resilience of VoIP (Voice over Internet Protocol) systems during mains power failure involves implementing strategies to;

• provide backup power
• and – maintain Internet connectivity.

Here are some common methods to make VoIP systems immune to mains power failure:

Uninterruptible Power Supply (UPS):

Deploying a UPS is a fundamental step in maintaining power during outages. A UPS has a battery that provides short-term 230V AC power to critical devices, such as VoIP servers, routers, and phones – allowing them to continue operating for a limited time. Note, however, that the UPS must have the capacity to power phone[s] as well as the broadband router to maintain the telephone service. If the broadband router is not powered during a power outage, then calls cannot be made or received.

As a secondary but important function, a good quality UPS will also act to ‘smooth’ mains power delivery by suppressing spikes and surges, thereby protecting your equipment.

If you have the specifications for the devices that are being powered through the UPS, then you can calculate its ‘rough’ backup time using the following:

1. Multiply the battery rating (in Ah) × the battery rating (in V) × the number of batteries × the battery efficiency (typically 80-85% for 12V lead-acid batteries).
2. Then – divide that number by the total load in Watts (W).

Power over Ethernet (PoE) with UPS:

If your VoIP phones support Power over Ethernet (those supplied by Foxhall Solutions will), you should be using PoE switches with a UPS. This way, WiFi networking equipment and phones receive power through their Ethernet cables, and the UPS can ensure continued operation during power outages.  PoE also allows multiple phones to be powered and backed up using a single ‘large’ UPS co-located with the PoE network switch and other core equipment.

It’s becoming common to use WiFi or DECT cordless technology to deploy desk phones (e.g. where cabling is difficult or prohibitively expensive).  PoE with a UPS will maintain power to most types of Wireless Access Points during an outage, but the phones themselves will need individual UPS units to keep them powered during a local mains power failure.

Backup Generators:

For larger installations or mission-critical environments, backup generators can provide extended power during prolonged outages. Generators can be set up to automatically ‘kick in’ when the mains power fails.

Redundant Power Supplies:

Deploying redundant power supplies for critical VoIP components can add an extra layer of ‘hardware’ reliability. If one power supply fails, the backup takes over seamlessly.

Cloud-Based VoIP Services:

Consider using cloud-based VoIP services. In this scenario, your VoIP system is hosted in a data centre which includes redundant power systems, UPS and backup generators. This can ensure continuous service of your phone system, even if there are wide-area power issues. Delivery of calls to and from handsets still requires UPS and PoE strategies implemented at your premises, however.

Cloud-based UCaaS platforms allow you to put VoIP extensions on mobile devices as apps – and therefore – can provide another layer of resilience by delivering calls to staff mobiles during a mains power outage at your business.

Redundant Internet Connections:

If your business has a ‘mission-critical’ need for Internet access, then ensure that your VoIP system has redundant Internet connections. If one connection goes down, the system can automatically switch to the backup connection, maintaining communication even if one network link fails.

Emergency Power Off (EPO) Systems:

Implementing EPO systems allows you to shut down non-essential equipment during a power outage, prolonging the operation of critical systems like VoIP servers. As a strategy, you need to identify and ask if any core device not powered through a UPS is non-essential – as that device WILL power off during an outage. In most cases, EPO can be implemented by simply not plugging non-essential equipment into a UPS.

Regular Testing and Maintenance:

Regularly test backup power systems and conduct maintenance to ensure that they are in working order. Replace batteries in UPS units as needed. Many UPS systems have indicator LEDs and audible tones to advise you that it is time to replace the battery – but – a battery life of at least 5 years should be expected.

Power Monitoring and Alerts:

Implement power monitoring systems that can provide alerts in case of power anomalies or outages. This allows for proactive response and troubleshooting. Take note of any news reports regarding predicted power outages due to National or Local Grid supplier issues and approaching weather storms.  Plan to provide emergency power to maintain services based on the time you need to keep running in the event of a mains power failure. That could be for the whole duration of the outage – or just short term to set up alternative communications (e.g. to turn on UCaaS mobile apps).

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It’s important to note that the specific solution will depend on the type & scale of your VoIP deployment, budget considerations, and the criticality of the service[s] provided by your organisation. Give us a call at Foxhall Solutions to tailor a VoIP power solution to your specific needs and circumstances.