PTT Unifoon (NSEM)

Unifoon beige rood en wit
Unifoon beige rood en wit

Introduced in 1981, together with the Ericsson Diavox this was the first telephone in the PTT inventory that was specifically designed as a push button telephone.

The Unifoon is a straight and angular designed telephone, with the handset placed laterally. Under the handset is a card for a list of important telephone numbers. The telephone has an earthing button, in the same colour as the body shell. Inside is a simple printed circuit board, on which a dial unit is mounted and a mechanical ringer, that has a volume adjustment wheel.

PTT reclame 1981
PTT reclame 1981, Unifoon en Diavox

Of both the Diavox, as well as the Unifoon there was also a rotary dial version, but these were never issued by PTT.

Unlike the T65 touch tone, the Unifoon had a version that had push buttons, but still dialled pulse (IDK, impulse druk kiezen) and a version that had push buttons and dialled DTMF (TDK, toon druk kiezen). This allowed subscribers on an exchange that supported only pulse dialling to have the option of buying a push button telephone. The IDK version is the most common. The IDK version does not have the * and # next to the 0 key.


The Unifoon was developed from a model that was designed by ATEA, in Antwerp, in the 1970’s; the model  8000. This key system telephone 8000 lead to the development of the U77, a telephone used by RTT (Regie van Telegraaf en Telefoon, the Belgian state telephone company). This U82 was produced by ATEA, but also by its competitor BTMC. BTMC was the mother company of NSEM in Rijswijk (the Netherlands) and so this design ended up in Holland. Another version of the model 8000 was sold in the UK under the name Rhapsody and also in the USA this model was sold in limited numbers.

PTT folder 1983 achter
PTT folder 1983 achter


PTT Unifoon ad 1987The Unifoon was issued by PTT in four different colours: beige, ivory, white and red. With time the available colours varied, with beige available during the whole period that the Unifoon was offered by PTT.

Queen Beatrix had one too

Our former queen Beatrix used to have on in her office. She used her Unifoon until the very end of her reign. The original black line cord was swapped for a white one, probably because the black one was too short.

Koningin Beatrix, premier Rutte en een Unifoon © RVD, foto: Frank van Beek
Koningin Beatrix, premier Rutte en een Unifoon
© RVD, foto: Frank van Beek

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