Specifications
- Application
- wire intercom for mines, lifts, funiculars, forests and building sites (up to 4 stations)
- Power supply
- 13.5 V dry or semi-dry batteries
- Power consumption
- 1.2 W idle, 6 W at full output
Sources: [4]
Description
The R 6902 Exterfon is an outdoor intercom (Exterfon), made by IEMI in Bucharest and designed at the ICE research institute in Bucharest [1].
ICE’s radio networks laboratory (1980–1991) built radio networks for oil fields, police traffic control and the Danube–Black Sea Canal; two of its products went into production at IEMI [1].
IEMI’s production table lists 8,415 made in 1973–1985 [2]. Its list price, set in 1982, was 1,800 lei [3].
Annex III.2.15 describes it as a wire telephone for simplex communication between up to four stations connected in parallel, for mine galleries, lifts, funiculars, forests and building sites. It consisted mainly of an amplifier, a loudspeaker and a power supply; switching a station from listening to talking turned the loudspeaker into a microphone, the gain was adjustable in steps, and its robust, weatherproof construction let it work outdoors in hard conditions. Its range was up to 10 km, the loudspeaker could be heard well up to 100 m away, and it gave up to 3 VA into 3 Ω over 300–3000 Hz [4].
Gallery
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Schematics
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Documents
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References
- [1]N. Millea (coord.) et al. – „Electronica românească. O istorie trăită”, vol. II „Electronica profesională”, AGIR, section II.4.7 „Laborator pentru realizarea de rețele radio”, p. 134
- [2]N. Millea (coord.) et al. – „Electronica românească. O istorie trăită”, vol. II „Electronica profesională”, AGIR, annex III.2.4 „Producția IEMI – radiotelefoane”, pp. 387–392
- [3]N. Millea (coord.) et al. – „Electronica românească. O istorie trăită”, vol. II „Electronica profesională”, AGIR, annex III.2.5 „Lista cu prețurile produselor – IEMI”, pp. 393–396
- [4]N. Millea (coord.) et al. – „Electronica românească. O istorie trăită”, vol. II „Electronica profesională”, AGIR, annex III.2.15 „Echipamente de radiocomunicații profesionale”, pp. 678–689