Zweidraht-UEbertragungseinrichtung

摘要

1,141,695. Automatic exchange systems. INTERNATIONAL BUSINESS MACHINES CORP. 9 May, 1966 [10 May, 1965], No. 20413/66. Heading H4K. [Also in Division G1] Apparatus for transferring signals from an input line to one of a plurality of output lines includes means to modulate a beam of light in accordance with a signal on the input line, a plurality of photosensitive transducers each associated with an output line and means in the light path operable in response to a signal distinctive of a particular output line to deflect the light beam to the transducer associated with the particular output line. An exchange for selectively interconnecting telephones 11, 12, 13, 14, Fig. 3, comprises a plurality of birefringent plates E1a-E4a and E4b-E1b separated by electro-optic devices, e.g. KDP crystals which rotate the plane of polarization by 90 degrees. The speech signals from telephones 11, 12, 13 and 14 modulate light-emitting diodes D1a, D1b ... D4a, D4b, respectively. The birefringent devices are arranged to transmit the ordinary ray without deviation and the extraordinary ray displaced by a distance equal to the spacing of the diodes. If a call is to be set up from 11 to 13 electro-optical devices EO1a and EO3b are energized. This makes light emitted from diodes D1a ... D4a extraordinary and therefore displaced downwards by all the birefringent plates E1a ... E4a and only light emitted by diode D1a passes through the aperture 25. This light is deflected upwards by plates E4b and E3b before being made ordinary by the electro-optic device EO3b whereafter it passes horizontally to the photo diode P3a associated with telephone 13. The return speech path from D3b to P1b is simultaneously set up by energization of electro-optic devices EO3d and EO1c. For operation as a time division multiplex system, telephones 11-14 are scanned by a scanner 44 which passes the calling and called members to a central control 48 which circulates these numbers through memories M1 and M2 to close selected switches S1a- S4a and S4b-S1b energizing the electrooptical devices. In another embodiment, Fig. 4 (not shown), the thickness of the birefringent plates are in a geometrical progression with common ratio 2 and a combination of electrooptic devices may be energized which is in effect a binary coded indication of the calling or called number.