Modernising Emergency
Lift Phone Communications

– with digital voice calls fully compliant with BS EN81-28:2022

Modernising Emergency
Lift Phone Communications

– with digital voice calls fully compliant with BS EN81-28:2022


1st June, 2024 by Noel Sesto | ControlFreq

Before you upgrade PSTN emergency lift phones, read this.

ControlFreq is a specialist provider of mobile communication systems, since 2007. Mobile hardware, global SIM connectivity, cloud-based software, connected-solution design, mission-critical technical support and mobile technology R&D. This is what we do. 

Over past 6 months of extensive in-house and field testing we feel compelled to share our findings in this article. As the mobile networks operators started unbuttoning the past and unleashing the future, the real-world impact of such seismic change has become apparent, at least to those who've spent 6 months digging into it... 

The end of 3G is now well and truly in play. While O2 and 3.UK, have not actioned the shutdown yet, both EE and Vodafone signalled the final days as end of February 2023. With 3G unavailable, voice calls must be routed via either 2G or on the new voice standard for the future, 4G-VoLTE (or 'mobile VOIP'  – calls over 4G data). This presents a problem as we can't rely on only 2G services and, at the time of writing, VoLTE audio is not yet supported by the roaming connectivity providers.

The lack of Roaming Partner agreements with UK operators for 4G-VoLTE audio services has been a significant issue. 4G-VoLTE service (voice-over-LTE or effectively 'mobile-VOIP') has been severely delayed by the UK mobile network operators (MNO) who control the frequencies the roaming partners utilise. These delays have caused many existing GSM-based installations in the field, that all of a sudden need VoLTE, to become hit & miss while the roaming partners struggle to connect calls and route reliable DTMF tones using 2G and 4G unfit for purpose.  

Any hardware utlitising roaming SIM services requires VoLTE to enable 4G-VoLTE audio and reliable DTMF service. Without VoLTE, the 4G hardware is forced to switch to 2G, or as in many cases it connects to flakey 3G signal. The end result is, due to network switching instability voice calls are not always connected on the first attempt. The challenge for GSM only hardware in this situation is until reliable 'multi-network' VoLTE service is available on roaming SIM cards, it will remain this way. When will this be? SOON! – we've been told since January 2023... and as or 17th June 2023, we're still waiting...

The UK MNO's triggered the '3G shutdown' before roaming partners had access to VoLTE service which means roaming SIM in the field that used to work OK, have begun failing. The roaming partners haven't got VoLTE services tested , commercialised or deployed in time to avoid the gaping chasms in service level becoming apparent. 

Since the commencement of  'The Digital Upgrade' by UK mobile networks,
mobile voice & DTMF services are NOT as stable as they should be for upgrading communication services in critical life service applications such as emegency lift phones.

It's wise to consider carefully the choice of 'digital upgrade' – which will be the primary and subsequently back up communication path/s to mitigate critical failure? Does the device have multiple redundant communication paths??


The current state of UK Mobile Networks

To try and understand the future, we have to first step back to the past. The new method of voice and data transmission over mobile networks is in a transitional phase. What the mobile networks tell us and what we experience in the real world are wildly different. The instability during any major infrastructure transition becomes apparent as intermittent issues expeirenced by the user of the connected equipment. This needs to be considered when choosing the safest and most reliable lift phone communication technology for the future of emeregency lift phone communications.

While GSM mobile networks have been around for as long as anyone can remember, times are changing and significantly. A seismic shift in mobile voice & DTMF transmission is underway. Not all mobile network operators (MNO) are on the same page, actioning upgrades at the same time or even at the same level of technological advancement – again, this all just spells confusion, uncertainty and ultimately risk of failure.

LEGACY: Voice & DTMF traffic utilised 2G & 3G mobile transmission frequencies with voice calls running over the 'voice channel' and DTMF signals over the 'data channel'. 

TRANSTIONAL: If 4G hardware is installed, and no VoLTE service is available on the SIM being used – or a lack of VoLTE hardware support, the device will connect to the network using 4G frequencies by default. As it can not facilitate the voice call over 4G without VoLTE, the device is required to handle a realtime network switch down to 2G or 3G to connect the voice call. What we have found is this does not always happen and the call can fail. Try again, it may work however, sometimes, numerous attempts are required to connect the call. This kind of instability is 100% down to the network transitonal phase and unavoidable until such time as the networks stabilise full and appropriate service delivery to support modern communication needs. 

FUTURE: VoLTE carries both voice & DTMF carry over a single data channel for reliable and consisent connection and behaviour. There is no need for networks switching between 2G/3G/4G.

Voice services, for hardware utilising roaming SIM cards via UK mobile networks, has become unstable in terms of voice call connection and and DTMF reliability.

Since the final deadline for 3G shutdown was announced by Vodafone and EE at the end of February 2024, voice & DTMF has either fallen back to 2G service or failed to behave correctly.

When 4G-VoLTE audio services are openly available, consistent, reliable functionality will follow. 

The Challenge of 'GSM-Only' for Emergency Phone Lines

Network Outages: GSM networks, while widespread, aren't immune to outages. During a blackout or network failure, communication can be completely cut off. 

Signal Strength: In basements, lift shafts, or buildings with poor cellular reception, GSM signals may be weak or unreliable.

Limited Monitoring: GSM phones typically only alert when a call is made, offering no proactive monitoring of the lift's condition or communication system.

Lack of VoLTE Service: Roaming partners not providing full multi-network connectivity due to lack of UK partner agreements on VoLTE services rendering what was a 4 network roaming solution for back up service down to a single, possibly dual, network VoLTE service – when available.

The Digital Upgrade 'Multi-Layered Approach

Modernizing emergency lift communication involves adopting a diverse range of technologies to create a fail-safe system:

LAN/WiFi Integration: By connecting lift communications to a building's local area network (LAN) or WiFi, you create a reliable communication path, even when cellular networks are unavailable. This allows for faster data transfer, potential for video communication, and integration with other building management systems.

Multi-Network Roaming SIM Cards: These SIM cards automatically switch between available cellular networks, ensuring a connection even if one provider experiences an outage.

Real-Time Monitoring: Advanced systems can continuously monitor the lift's operation, battery levels, and signal strength. Any anomalies trigger alerts to maintenance personnel, often before a breakdown occurs.

Battery Backup: In the event of a power outage, battery backups ensure the communication system remains functional, allowing trapped passengers to call for help.

Mains Fail/Restore Alerts: These alerts notify maintenance personnel of power failures and restorations, allowing them to quickly assess and address any issues.Cloud Management and Monitoring: Cloud-based platforms provide centralized control and monitoring of multiple lifts across different locations. Real-time data analysis can identify trends, predict maintenance needs, and improve overall safety.


Advantages of a Multi-Faceted Approach

Enhanced Reliability:
By not relying solely on GSM, the system remains operational even during cellular outages.

Faster Response Times: Real-time monitoring allows for quicker identification of problems and dispatching of assistance.

Improved Safety: Proactive maintenance and early issue detection reduce the risk of breakdowns and entrapments.

Greater Flexibility: Cloud management simplifies system updates and configuration across multiple locations.

Compliance & Regulation

It's important to note that any upgrades to emergency lift communications must comply with the relevant UK safety standards BS EN81-28:2022. The standard outlines requirements for reliability, battery backup, and other critical aspects of the system.

Looking Ahead: The Future of Lift Communication

The future of lift communication is likely to involve even greater integration with the Internet of Things (IoT), allowing for predictive maintenance, personalized passenger experiences, and potentially even voice-activated assistance within the lift.

In Conclusion: Upgrading emergency lift communication to a multi-layered, digital system is a vital step in ensuring the safety and well-being of passengers. By embracing a solution focused on multiple communication paths and moving beyond a GSM-only solutions, building owners and managers can create a more resilient, reliable, and ultimately safer environment for everyone.

What's the belt & braces solution for emergency lift phone  communications?


Search no more! The ultimate 'black box' all-in-one Plug & Play solution is available from ControlFreq as an end-to-end service.

Complete solution including hardware, connectivity, voice calls (in & out), cloud monitoring and in-house dashboard of realtime status of every device in the field.

Take your lift estate from legacy to future in a few shorty minutes by simply plugging the lift phone communicator phone line into RETRO-LIFT for an instant digital voice communication upgrade.

LAN primary w/ WiFi & Dual-SIM back up

SIP digital audio & VoLTE audio support

Realtime cloud monitoring & event logging

8 hour battery back-up with 4 hours call time

7-day UK technical support by phone

End-to-end service with single point of contact

Full compliant with BS EN81-28:2022




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RETRO-LIFT | Emergency Lift Phone Retrofit Upgrade (BS EN81-28 Compliant)

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