LACS protocol offers the opportunity for an open standard

The lift industry needs a common, open IP alarm protocol. The European Lift Association (ELA) has created an important basis for this.

However, to enable general applicability, greater depth of detail and additional functions are required. The LACS (Lift Alarm Communication Standard) initiative fills these gaps and adds important specifications for true interoperability.

By Joachim Klingler

The starting position: Emergency communication is in transition. Classic fixed lines are disappearing; IP-based networks are the standard. In practice, Voice over LTE (VoLTE) has established itself as the state of the art. Transmitting well-known tone-based protocols over these IP audio channels functions reliably as a bridging technology.

Photo: © Telegärtner Elektronik

However, as requirements increase, differing proprietary protocols and the transmission of tones within the voice channel hinder new functions. The future must be “IP-native”. Only then can modern security mechanisms be utilised and data transmitted efficiently parallel to voice.

The problem: lack of standards creates isolated solutions

Currently, there is no protocol that uses IP technology natively while functioning across different manufacturers. ELA (TELCO Working Group) has created an important foundation for this: an approach based on the SIP standard (known from VoIP), in which alarm data is sent as XML messages.

The problem: the ELA definition only covers the minimum requirements of EN 81-28 (remote emergency call). Details remain open. If manufacturers were to implement this individually now, incompatible “dialects” would emerge. A device from Manufacturer A would not be able to communicate with the Alarm Receiving Centre (ARC) of Manufacturer B.

The solution: LACS creates clarity

This is where the Lift Alarm Communication Standard (LACS) comes in. LACS is not in competition with the ELA definition but is a practical extension to guarantee interoperability and extended functions. Through clear sequence diagrams and sample messages, implementation is facilitated and misunderstandings are avoided.

Additional advantages of LACS at a glance:

Extended diagnostics: LACS defines messages for faults that go beyond the emergency call (e.g., defects in the alarm button or internal bus).

Separate voice test: Since data no longer runs in the voice band, LACS checks via a defined test procedure separately whether the voice connection to the ARC is established.

Additional capabilities: LACS also standardises add-on features such as the two-sense alarm (text-based) or camera images. The ARC automatically detects the supported functions.

An open initiative

LACS is an open working draft (Open Source). Besides Telegärtner Elektronik and Iotcomms, companies such as Esse-ti, Serv24, Thor Parts, and Prysm are already supporting the project. The goal is a stable definition by April 2026.

First implementations are already underway to incorporate practical feedback directly. In medium term, the results are intended to flow back into ELA guidelines and standards (such as CLC/TS 50134-9).

FAQ: briefly explained

Why is a native IP protocol needed? To ensure secure communication in line with the state of the art in the long term, a suitable data protocol is required parallel to voice. Furthermore, this integrates features such as cameras, text-based communication, and detailed diagnostics.

Does LACS replace the EN 81-28 standard? No. LACS is the technical “tool” used to implement the requirements of the standards securely and uniformly.

Who can use LACS? Everyone. The protocol is available under the free “CC BY-SA” licence on Codeberg.

The author is CTO at Telegärtner Elektronik.

More informations: Link to specification & download: codeberg.org/telegaertner-elektronik/LACS-Protocol/

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