L. M. ERICSSON DIAVOX

L. M. ERICSSON
TELEPHONE - DIAVOX

Diavox

The Dialog telephone was first produced in early 1960's and was introduced into Televerket's range in 1965. By the middle of the 1970's they become unfashionable, even though it could be equipped with a keypad for pulse or tone and the number of colours increased from three to six.

The original black, grey and white had been supplemented with the new colours red, light yellow and dark green.

The introduction of new exchange systems was one of the motives to construct a new telephone model which from the very beginning was intended for press button dialling. In 1975, Televerket and LM Ericsson decided to start developing a new phone, jointly with the development company, Ellemtel. It was specified that the new telephone should be the basis for specialist models, be Dial, LD or MF and have a better quality of speech.

Four different design companies were commissioned to produce proposals for the exterior design of the new phone. The model selected for production was designed by Carl-Arne Breger, whose designs can be seen many Swedish homes, e.g. the Flora package, the ABC-80 computer, the plastic water jug and the Ericofon 700.

L M Ericsson produced the first Diavox 100 phones in 1977 and 1978 and a model without a keypad or dial was introduced in 1979. The initial telephones were fitted with beige cover, black handset, high-resistance adjustable bell, electret microphone and electronic speech circuit with automatic attenuation compensation. Production of the Diavox telephone ceased in 1989.

The Diavox replaced the Dialog telephone as Televerket's standard telephone.

Diavox's shape insured that there was plenty of room for buttons, display etc. The coloured part of the cover was cheap and easily replaceable by the subscriber. For reasons of cost and reliability, the Diavox telephone kept the polarized bell as a signaling device although it has actually been replaced by tone ringers in a number of prototypes. Otherwise, electronics have been used to a large extent. The carbon microphone, which began to be used as early as 1888, was replaced by a electret microphone with significantly better sound characteristics.

Unlike the carbon microphone, the electret microphone requires an amplifier. This was built into the same capsule as the microphone. Electronic components were fitted to the circuit board placed directly under the front cover.

The base model was available in two basic versions: the original model and a more modern, the Diavox-II, which unlike the original model has a volume control and cords with modular connectors.

In the Diavox-II, the amplifier for the microphone has been moved from the microphone capsule to the main circuit board. The microphone cord unlike the older model, which only had two conductors, has four, two for the microphone and two for the earpiece.

The Diavox telephone was available in a large number of variants. The base model was been manufactured with 10, 12 and 13 buttons. The ten-button model was intended for older switches that can only receive pulse selection. The twelve-button device was an MF tone device without a Recall button and was intended to be used with older switches that have been supplemented with tone receivers. The model with thirteen buttons was an MF tone device with a Recall button, intended for AX switches and modern company switches. Ericsson has also produced devices with 11 buttons where the Recall button did not have the usual time break function, but instead is used to connect the line to earth. This Recall button has the same function as the regular Recall button but is used with pulse dialing instead tone dialing.

A Diavox telephone you rarely see is the one equipped with a regular "old fashioned" dial. This is because the model was never used on Televerket's network.

Within the casing there is also room for amplifiers and speakers, as in the Diavox 200, which was used in manager-secretary arrangements (by use of two-lines).

Special models have also been produced, analogue and digital, for connection to different types of exchanges.

Ericsson produced a total of 6.5 million complete telephones and kits for manufacture abroad. The production continued until 1989. Additionally, a large number of Diavox sets, for the Swedish market, were manufactured by TELI.

Taken from an article by Ove Svensson

Additional Information

The Diavox was produced in three basic variants with 10, 12 or 13 buttons. The 10-button (904) was LD (Dial pulses or IDK). The 12 button, 921 model and the 13 button, 901 model were manufactured with tone dialing (MF to international standards or TDK). LM Ericsson manufactured 6.5 million devices and many were exported worldwide. The Diavox was available in a large number of different versions, e.g. loudspeaker, manager/secretary, line recorder, cover in precious wood, cover in leather and a small number with a finger plate.

The wooden cased sets were called Royal Wood and were available in Walnut, Mahogany, African Rosewood, Cherry and Birch. As these were made of wood the grain was different on each telephone. These were produced with either LD or MF keypads. Each telephone came with a certificate of authenticity and a serial number. These telephones were fitted with a bell, which had a mechanical volume control fitted in the base.

A model called the Royal 100 was introduced for export to the USA and this was available with three different combination sets of three colours. Each set consisted of a Diavox MF telephone with two extra cases, which the customer could change.

A wall type was also produced and these were known as the Diavox 901 and 933, the 933 being the model with a recall button.

Marketing Names
Diavox 100 - Basic telephones or variants with the same cover
Diavox 120 - Telephones with headset
Diavox 125 - Telephones with two exchange lines
Diavox 130 - Telephones with abbreviated dialing and loudspeaker monitor
Diavox 150 - Executive/secretary working
Diavox 200 - Loudspeaking telephones
Diavox 250 - Loudspeaking bases
Diavox 824 - Telephones for use on telephone systems (Max 8+24)

There were 20 different plastic covers, of different colours, including white, black, blue, red, mustard yellow, green, silver and gold. These covers could be easy changed by releasing the two screws on the base and was advertised as a customer function.

Many were sold in Holland and the Dutch PPT introduced the Diavox S to their consumer market in the colours ivory white, beige and black. The handset was the same colour as the case. By means of interchangeable cases the phones could be obtained in numerous colours as many colour combinations were possible. The colour range was extended later and included: red, yellow, blue, green and maroon (please see the colour chart link below). These telephone conformed with the Dutch PTT standard NORM 51. Some of these telephones are labeled as Diavox IDK (LD variant) and Diavox TDK (MF variant).

Ericsson produced push-button Diavox telephones for Saudi Arabia. They featured the Saudi coat of arms and arabic numbers on the keypad buttons. The Saudi government ordered 400,000 telephones from Ericsson, the last being delivered in 1989.

In the UK, BT marketed the Diavox telephone as the Astrofon. The engineering designations were Telephone Special Range No. 1003 or 8003, depending on the type of line cord fitted.

Variants
DBA 101 - Dial and No dial
DBA 102 - LD press button
DBA 103 - MF press button
DBA 122 - LD press button - Headset use
DBA 133 - MF press button - Abbreviated dialing
DBA 180 - Press button - System telephone
DBA 191 - Unknown
DBA 192 - Press button - System telephone
DBA 202 - LD press button - Loudspeech
DBA 203 - MF press button - Loudspeech
DBA 701 - System telephone
DBA 703 - System telephone