This article outlines the history of Telephone Answering Machines and Devices that were developed and produced by Willy Muller and continued by Alois Zettler GmbH, Germany in the 20th century.

Willy Muller of Munich, Germany developed the "Tele-Phonograph" System during 1935-38. It was based on magnetic steel wire recording method, with complex electro-mechanical controllers, using cams for sequence timing. It was intended for operation at the telephone central exchange facilities.


Due to WW2, Willy Muller moved his operation to Switzerland and in 1946-47 he introduced an improved system named "Ipsophone". About 700 units were produced.


Mass production of commercial telephone answering devices, could take place only when the telephone network company or authority in a country, granted an approval to connect the device to the telephone line at the subscriber's premises.The first commercial telephone answerers that were approved for use at the subscribers' premises (business offices, professional persons and home use), began in the late 1950's in Germany and Europe. 


Willy Muller developed in the mid 1950's the first commercial telephone answerer, the "Alibiphon VA 58". It was introduced in Germany in 1957 and was the first authorized Telephone Answering Device by the Gernman Post, to connect to the subscriber's line. The Alibiphon VA 85 is an answering only device, but with an option to connect an external recorder, to record incoming messages. It operates with two vacuum tubes (EF40, ECC40). The production of the Alibiphon was made at Fredr. Merk Telefonbau A.G., Munchen.

At the beginning of the 1960's, a modified version "Alibiphon VA 58/11" was introduced. Mechanically it is the same, but the vacuum tubes circuitry was replaced by two boards with Germanium transistor circuitry. 

The recording media of the Alibiphon is a disc covered with a magnetic plastic layer. A magnetic play-record head scans the disc like in a record player. The following picture shows the disc mechanism and the head assembly. Willy Muller designed in the fifties the basic voice or data recording system that about 30 years later, became the heart of every hard disc memory in computers.

ALIBIPHON VA 58 (1957)


The next telephone answerer that was developed by Willy Muller was the"Alibicord". It sends an answering message and records up to 22 incoming messages. The recording method is based on cylinders coated with the same magnetic plastic layer as in the Alibiphon disc. It is similar to the Edison wax coated cylinder phonograph. A narrow cylinder is used for the outgoing message and a wide cylinder is used for recording up to 22 incoming messages of 30 seconds each.


An additional recording disc is mounted on the main shaft, for a second outgoing announcement. It is activated when the recording cylinder is full with 22 messages.


The controller and timing sequence in the Alibicord (like the Ipsophone and the Alibiphon) are electromechanical with multi-layer cams and contacts. The production of the Alibicord of Willy Muller was made by Alois Zettler GmbH, Munich during the early-mid 1960's. 



The next telephone answering machine of ZETLER was the ALIBIPHONOMAT. It includes the same magnetic recording hard disc of the ALIBIPHON of Willy Muller for the outgoing message. A reel-to-reel tape recorder is used to record the incoming messages. The total time of the tape is 90 minutes, which enables recording of hundreds of messages. The duration of the incoming message is unlimited and is determined by a voice operated relay.


The ALIBIPHONOMAT was produced at the beginning of the 1960's and was used by large companies and organizations.  


The A-ZET is an answering only device like the ALIBIPHON. The outgoing message is recorded on a tape loop that is stored in a special cassette. The duration of the outgoing message can be changed by changing the length of the tape loop. 

 A-ZET (1966)

There is a connection for external tape recorder to record incoming messages. An electro-magnetic counter shows the number of calls that have been answered.


The A-ZET was produced by ALOIS ZETTLER in the 1960's. 



The A-ZET C is a newer version of the A-ZET, using a drawer type tape loop cassette. 


ALIBINOTA was introduced to the market at the beginning of the 1970's and replaced the ALIBIPHONOMAT. It had additional capabilities, like remote incoming messages listening from any telephone in the ALIBINOTA F Version. In Version FL, it is possible also to erase incoming messages


A new generation of the ALIBICORD started with the ALIBICORD 3 and continued with the ALIBICORD 34 and the NOTATRRONIC.


The outgoing message drawer cassette is like in the A-ZET C.This is the first time that ZETTLER used the "Compact Cassette" recording system for incoming messages. 



The line of ZETTLER Telephone Answering Devices continued with the progress in the electronics circuitry and digital voice recording technologies. The newer lines used MICRO-CASSTTES for outgoing message and incoming messages in the ZETTLER CORD-COMPACT and TAB-COMPACT telephone answerers

 CORD-COMPACT                                  TAB-COMPACT                               ZET-COM 250                                          ZET-PHONE 42                                        

With the development of DSP circuitry and Digital Audio technology, the new lines of ZET-COM telephone answerers used Digital Memory for outgoing and incoming messages. The next product was the ZET-PHONE - a telephone with built-in telephone answerer, which appears to be "the last telephone answering device".


This is the end of the Telephone Answering Device Era. From now on, the digital PABX capabilities enable the telephone subscribers to record an outgoing message and get incoming messages, which are digitally stored at the PABX server.  

© 2023 by Success Consulting. Proudly created with                TELECOM MILESTONES Along the History of TELECOM and Electronics Technology

This site was designed with the
website builder. Create your website today.
Start Now