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Circuit for Selecting Data Input Stations

IP.com Disclosure Number: IPCOM000094490D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Diehl, V: AUTHOR [+2]

Abstract

This circuit serves to select data input stations for the purpose of connecting them to a central computer.

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Circuit for Selecting Data Input Stations

This circuit serves to select data input stations for the purpose of connecting them to a central computer.

Irrespective of which input station requests a connection, all input stations are interrogated in succession, starting with the first one. As soon as the requesting input station is found, all input stations preceding it are blocked and only those following it are able to call for a connection. After the data of a given input station has been transmitted, that station is also blocked. In case another request is still waiting, the respective input station is sought in the described manner. As soon as all input stations are blocked, the blocked condition is terminated and a new cycle can start.

The drawing indicates three input stations I... III. Each is, when one of the relays S is energized, connected through a data transmission line, not shown, to computer 1CU. A connection is initiated by operating the associated contacts 1 and 2. Through the operated contact 1, no matter to which input station it belongs, a voltage tU is supplied via the computer to contact 2 of input station 1. If that contact has been operated, relay S1 is energized and completes the connection. On the other hand, with contact 2 of input station 1 not transferred, the voltage -U after having undergone a certain delay in a delay unit D reaches contact 2 of input station II. If that contact has been operated, relay S2 is energized. Otherwise the...