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Telephone model from the 1970s.

Telephone model from 1975. The first telephones for tone signalling of numbers were put to use in 1975 in areas with computerised telephone exchanges. The principle behind tone signalling is that each digit has a standardised frequency or tone which is sent to the exchange. This model is a modified standard 1967 telephone where the numbers dial has been replaced by a push-button keyset.
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Título:
Telephone model from the 1970s.
Descripción: Ver traducción automática
Telephone model from 1975. The first telephones for tone signalling of numbers were put to use in 1975 in areas with computerised telephone exchanges. The principle behind tone signalling is that each digit has a standardised frequency or tone which is sent to the exchange. This model is a modified standard 1967 telephone where the numbers dial has been replaced by a push-button keyset.
Crédito:
Album / Universal Images Group / Universal History Archive/UIG
Autorizaciones:
? Cesión de modelo: No - ? Cesión de propiedad: No
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Tamaño imagen:
5100 x 3930 px | 57.3 MB
Tamaño impresión:
43.2 x 33.3 cm | 17.0 x 13.1 in (300 dpi)
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