Replacement of a Siedle in-house telephone

From the 50s to the 90s of the last century, the so-called 6+n system was the state of the art in door communication technology. Intercoms of this type have been installed millions of times; many have now reached operating hours that require replacement. This can be done without any complex installation: the Siedle replacement telephone HTA 811 fits seamlessly into an existing system of the 6+n system. With an IQ in-house telephone and the Siedle app, the older systems even have access to mobile door communication.


Modernisation made easy

Cover up old drill holes or dirt – Siedle’s retrofit panels mean there’s no need for any plastering or painting. They ensure tidy, precision modernisation, both inside and out! Take a look at our video and see just how quick and easy it is.

Replacement of a Siedle in-house telephone – an overview

Siedle IQ-Haustelefon Austausch

The Siedle app. For systems from 1952 onwards.

Mobile door communication is possible even with older intercom systems: Just upgrade them with the Siedle IQ in-house telephone and the app. Users can connect to the digital world, regardless of how old their system.

Go to Siedle IQ
Siedle Haustelefon in PVD Schwarz

From old to something to behold.

The HTA 811 replacement model comes in the same variety of materials and colours as the current Siedle indoor call stations. So replacement provides a visual upgrade as well as a technological one. An electrician will clarify the requirements on site, calculate the work involved and submit a binding offer.

Go to specialist partner near you
Siedle Haustelefon Nachrüstblende

Modernisation with the Siedle retrofit panel

The Siedle retrofit panels cover the wall cut-out precisely where old devices leave e.g. colored edges, drill holes or a flush-mounted box that is too large. There is no need for plastering or painting; retrofitting is quick and easy.

To the product

The HTA 811 replacement telephone replaces these old Siedle devices

The HTA 811 replacement telephone replaces an impressive eight generations of older Siedle in-house telephones installed using the 6+n system. This overview shows which ones these are.


The LN 7145, LN 7150 AND S 7150 models with the legendary Schrillo bell are available with three, five or ten call buttons.


The pebble grey housing of the HT 111 features two buttons for door call, door release and light as well as a two-tone chime.


The HT 311 with its characteristic buttons and list of names under the receiver is a classic from the 1970s.


The HT 351 comes in light and dark brown, beige or orange. And with two or four signal lights.


The HT 411 has a no-tangle cord and two buttons with key symbol and a red dot for door call or light.


The HT 511 typically features a large door release or nine buttons and a field with three function elements.


The HT 611 comes in black or white. The door release and function buttons can be pressed when the receiver is down.


The HTA 711 has a plug-in cord, light button and door release button as well as one tone each for door and storey call.

To the product
Interested in replacing a Siedle in-house telephone? All contact partners at a glance:

Information for builders

Siedle door communication is incredibly versatile.

Who you can trust

Durable and retrofittable

A Siedle system is a safe investment. Because we develop our systems for a long service life. And when developing new products, we attach great importance to backward compatibility and update capability.

Quality and sustainability

Simple. Secure.

Siedle products provide functions that make the lives of the people using them simpler and more secure. We avoid excessive and fussy complication in favour of greater clarity.

Technology for people

Made in Germany

We are a high-tech company that uses the latest production methods. It’s also traditional human qualities and skills that give our products their very own character.

Made in Germany