Browse Prior Art Database

Serial Loop Fault Isolation Technique

IP.com Disclosure Number: IPCOM000084108D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Barber, RR: AUTHOR [+3]

Abstract

U.S. Patent 3,564,145 to Herman Deutsch et al discloses a fault isolation technique for use in a serial loop data transmission system. According to the patent, when terminals connected in serial loop detect no data or mutilated data conditions, each generate signals including a unique terminal address which, after a predetermined period, identifies that terminal immediately following the fault in the loop. This technique has been called beaconing since the terminals send out a beacon message which identifies the terminals, and the terminals eventually terminate transmission when they receive a proper beacon message. Thus, the beaconing terminal immediately following the fault eventually transmits beacon messages which are received by a central control station, to thereby identify the physical location where the fault exists.

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Serial Loop Fault Isolation Technique

U.S. Patent 3,564,145 to Herman Deutsch et al discloses a fault isolation technique for use in a serial loop data transmission system. According to the patent, when terminals connected in serial loop detect no data or mutilated data conditions, each generate signals including a unique terminal address which, after a predetermined period, identifies that terminal immediately following the fault in the loop. This technique has been called beaconing since the terminals send out a beacon message which identifies the terminals, and the terminals eventually terminate transmission when they receive a proper beacon message. Thus, the beaconing terminal immediately following the fault eventually transmits beacon messages which are received by a central control station, to thereby identify the physical location where the fault exists.

In certain terminal transmission systems, terminal addresses are not assigned until a particular terminal has logged on to the system. In these instances, the terminals are unable to transmit a unique terminal address under beaconing conditions until a logon has been completed. Described is a technique for rendering a beaconing system operative under the above conditions.

The fault isolation system described is particularly useful in a serial loop transmission system which utilizes a loop line control, as described in U.S. Patent 3,752,932 to Frisone. When a terminal, according to this technique, is power...