Browse Prior Art Database

Remote Unit Ready Indicator

IP.com Disclosure Number: IPCOM000092099D
Original Publication Date: 1968-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Celtruda, JO: AUTHOR [+3]

Abstract

The apparatus is for communicating, to a central system, Ready signals indicating the ready conditions of remote units. Bilevel DC signals, conventionally used to communicate Ready signals, cannot always be reliably transmitted by the remote units because they are connected by directional couplers. Thus, an AC signal is transmitted to the remote units and is received back at the central processing unit if the remote units are ready, if also not busy, to be accessed by the system. If the AC signal is not received back at the system, that failure to receive is interpreted as a Not Ready signal.

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Remote Unit Ready Indicator

The apparatus is for communicating, to a central system, Ready signals indicating the ready conditions of remote units. Bilevel DC signals, conventionally used to communicate Ready signals, cannot always be reliably transmitted by the remote units because they are connected by directional couplers. Thus, an AC signal is transmitted to the remote units and is received back at the central processing unit if the remote units are ready, if also not busy, to be accessed by the system. If the AC signal is not received back at the system, that failure to receive is interpreted as a Not Ready signal.

The apparatus of the central system, shown to the left and below the upper dotted line, is connected to the remote units RU1...RUN by transmission lines TL. The system clock supplies a square-wave signal, exhibiting forty nanosecond on and off times, over multiplex line 2. The latter includes a transmission line TL including non DC transmitting directional couplers not shown. Line 2 feeds each unit with the clock signal. Each remote unit includes an associated simplex line 3 which connects back to the associated one of Receivers 1...N via lines TL.

The details of the receivers are shown in connection with Receiver 1. When RU1 is in the Ready condition, Receiver 1 has an output on terminal 5. Similarly, when the other RU's are in Ready conditions, the corresponding receivers have outputs on their terminals 5. Each receiver has a bistable device 7 connected to a simplex line 3 which switches states each clock half-cycle which is received by and transmitted through RU1. If...