GB1039311A - Data handling system - Google Patents

Abstract

1,039,311. Electric selective signalling systems. BUNKER-RAMO CORPORATION. July 25, 1963, No. 29522/63. Heading G4H. An information retrieval system, for example for stock quotations, comprises a plurality of remote interrogating stations 10, Fig. 1, and a central station which comprises a first multiplexing means 16 to successively scan the interrogating stations for digital interrogating signals, a data retrieval unit 48, 46, and a second multiplexing means 76 to distribute the retrieved data to the interrogating stations. As described each interrogating signal comprise four dialled digits. These are assembled on a drum 14 by a " query logic " unit 24. The drum is arranged so that around its circumference there are 1024 segments each corresponding to one of the interrogating units and in which a dialled interrogating signal is assembled. Further tracks 33 on the drum provide appropriate clock and address pulses. When a complete four-digit interrogating signal has been assembled on the drum it is transferred, together with the address of the interrogating station 10 from which it came, via a temporary store 44, to a data retrieval unit 48-providing this unit is not " busy ". This unit then extracts the data called for by the interrogating signal from a drum store 64 and assembles it in a sixty-six six-bit word register 66. Each of the six-bit words corresponds to an actual speech word which it selects from a store of sixty-four speech words 78 for transmission back to the interrogating station via the second multiplex means 76. This occurs as follows. The sixty-six six-bit reply is written on the drum 14, by sixty-six heads 70 at a position around the drum corresponding to the interrogating station. The speech drum 78 has one speech word recorded on each track so that the complete vocabulary of speech words is presented repeatedly and simultaneously to the multiplexing means 76. An electronic switch 72 takes the data from a single read head 70 and is arranged to progress to the next head 70 after the speech drum 78 has made a complete revolution. The speed of drum 14 is such that each six-bit word for each interrogating station is read by head 70 about 25 times for each revolution of the speech drum 78. Thus in operation a single head repeatedly passes the six-bit words from its track to the multiplexing means 76 which selects and transmits the appropriate speech words to the interrogating stations. The system also includes the feature that to avoid any interrogating station having to wait for its reply until the switch 72 returns to the first head 70, the replay is shifted cyclically in register 66 before being transferred to the drum 14 so that the first word of the reply goes in the track which is next to be selected by the switch 72.