Many customers ask if it’s possible to connect autodiallers to in-building VoIP phone systems. Whilst in theory this may sound like a simple solution, there are some key risks that should be considered:

ATAs are difficult to setup and won’t always transmit the full 16 DTMF tones

The vast majority of autodiallers use Dual Tone Multi Frequency (DTMF) signalling to communicate information. VoIP systems require a piece of hardware called an analogue telephone adaptor (ATA) to handle DTMF.

An autodialler usually requires all 16 tones (0-9, *, #, A, B, C, D) to place alarm calls and 3-day test calls. It’s usually the A, B, C, D tones (sometimes called ‘timing tones’) that ATAs aren’t always able to support.

Power backup

This is the most critical issue as the whole call chain between the autodialler and the outside world needs to be backed up. This includes both the ATA and all the VoIP nodes in the call chain.

Servers which support VoIP systems may only be backed up for a few minutes to support a safe shut down of the server in the event of a mains power failure whilst regulation requires a minimum of 1 hour on standby and 15 minutes of talk time.

We frequently hear customers state that they plan to source a UPS system to backup the ATA – this may seem like a solution to ensure the ATA is operative in the event of a mains power failure, but this means there’s a responsibility to also maintain that UPS.

Normally, these UPS are stored out of sight and  it’s unclear who is maintaining them so the battery can drain or fail and no one would notice – until there is a trapping!

To prevent these issues, there are emergency lift phone solutions, such as the Digital Communications Platform (DCP) that have been designed with this in mind, so the battery is monitored and any issues are reported back to the Avire Hub.

Emergency systems should be reliable and secure to reduce risk. For this reason, a VoIP system is not a suitable communication link for an emergency system given all the risks it can present. At least not without significant investment and assurances from the building management to ensure the call chain doesn’t fail in a mains outage.


All this added equipment for the system (ATA, VoIP routers, etc.) falls into the definition of the ‘transmitter’ under EN81-28, so it sits outside the scope of the standards. Therefore, it’s not the responsibility of the lift company to manage or maintain these elements.

A GSM that forms part of the autodialler is firmly within the standard and therefore is the responsibility of the lift company. A solution such as the DCP offers lift companies the option for remote monitoring via the Avire Hub to ensure it works and it can be trusted to work any time there’s an emergency.

For a free consultation to find out how you can safely and reliably adapt your emergency communication system, contact our team.


Author: Milagros Gamero, EU Marketing Communications Manager at AVIRE

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