Improvements in or relating to telegraph keyboard transmitters

Abstract

Abstract 469,809. Code and facsimile telegraphy. CREED & CO., Ltd., and SALMON, R. D. Jan. 31, 1936, No. 2969. [Class 40 (iii)] A keyboard-controlled photo-electric transmitter for telegraphic code impulses (Morse or multiple-unit) or facsimile telegraphy comprises a drum 36 with rows of apertures or opaque and transparent portions rotatable within a drum 37 having an axial row of holes 38 adapted to be uncovered by shutters 39 controlled by the keys so that a photo-electric cell 35 is activated by a light-source 40 to transmit impulses. The light-source and cell may be transposed, and the light-source may be a mercury - vapour lamp fed with voice-frequency current. The code drum is carried by a shaft 42 which is driven by a spring wound by a constantly driven shaft (not shown) and is normally held by detent 16. When a key is pressed, magnet 17 releases the detent 16 and magnet 32 operates the key-locking bar 53. After the shaft has started, magnet 17 is released at contact disc 33 and, towards the end of one revolution of the shaft, relay 30 pulls up over disc 34 and releases relay 32 and the locking-bar. If a key is held depressed too long, 30 is held over the key contact and prevents re-operation of the detent magnet 17.

Inventors

No inventors recorded.

Bibliographic Details