Old telephone4/17/2023 ![]() In many contemporary pictures it stands in sole majesty on the hall table, often with the receiver held by the house’s mistress. ![]() Contemporary commentators praised the Ericsson’s phone for its simple, stylistically pure form, making it the favourite of functionalistic designers and a natural for the homes of the Swedish Welfare State. The integrated sculptural form departed from the more additive, engineer oriented design of the plate era. The new Ericsson telephone was completely formed in Bakelite with the cradle integrated in the actual casing. The US company Automatic Electric had made a Bakelite telephone as early as 1925 where everything but the metal cradle was made in plastic. For technical reasons, black was the only possible colour, or perhaps some related drab nuances. It is also comfortable to hold, does not draw moisture and is easy to keep clean, a contributing factor to its early use for both telephone receivers and toilet seats. The material is homogenous, evenly coloured and hard, with a lovely lustre. Basically they could be moulded into any shape possible, even the soft streamline shapes preferred. In many ways Bakelite was the perfect material for telephones at the time. That is about how long it took for the hot moulding compound to cure and then, when the Bakelite press spit the casing out, it was ready to assemble over all components on the bottom metal plate. It has been suggested that the time needed to make the casing was reduced from one week to around seven minutes. The management chose the new soft material Bakelite and the skilful designer Johan Christian Bjerknes was picked to solve the problem together with artist Jean Heiberg.įor the telephone manufacturers the move from plate to Bakelite was a total revolution. Ericsson badly needed a completely new telephone for automatic switching to hook up to the company’s successful, 500-switch system and to replace the old sheet metal telephones and their built-on finger dial. But Ericsson had bought that company in 1928 and asked AB Alpha in Sundbyberg in Sweden, another subsidiary, to make and distribute the Bakelite phone. Actually it was a Swedish-Norwegian collaboration since it was both developed and designed in Oslo by the historic manufacturer Elektrisk Bureau A/S. The units are powered redundantly by a common back plane connection.When Ericsson’s Bakelite telephone was first distributed world-wide in the 1930s it was called the Swedish type of telephone and set the standard for how a modern plastic telephone should look. Optionally, up to 8 FOI units can be mounted on CMA chassis adapters and installed in an RMC‐3101 or RMC‐2101 rack mount chassis. For standalone applications they can be powered by adding a PSQ‐4909 AC supply or a PSQ‐4920 DC power supply (not included). They are housed in the familiar FOI shielded can enclosure. ![]() The FOI-2971 and FOI-4972 are part of the FOI line of products designed for ruggedized mil applications. A typical link consists of an FOI-2971 connected to the POTS line and an FOI-4972 at the subscriber’s phone with a duplex fiber optic cable between them. Multimode optics on the units can extend the distance to 2km, while singlemode optics can further extend the distance to 20km. In addition, fiber optic cable offers much longer transmission distances than traditional telephone line cord wiring. FiberPlex recommends “R” units for high security applications because the units have added filtering and shielding for RFI suppression. Privacy of communications is also enhanced because the fiber optic cable does not radiate any emissions. The fiber optic cable is not susceptible to interference caused by impulse noise, crosstalk, or EMI. The units can be used in areas of high electrical noise or in and out of RF shielded enclosures. The FOI-4972 supports standard analog phones, STU-III (secure telephone unit) phones, STE (secure telephone equipment) phones, fax machines, and modems and supports Caller ID. ![]() The FOI-2971 and FOI-4972 provide complete electrical isolation for 2-wire telephone communications. ![]()
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