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Polarity Tester for Two Wire Serial Loop Communications System

IP.com Disclosure Number: IPCOM000082194D
Original Publication Date: 1974-Oct-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Palounek, LR: AUTHOR [+2]

Abstract

Described is a polarity tester which may be used to test polarity and continuity of a two-wire serial loop communications system. An example of a two-wire serial loop in which the interfaces to the serial loop are provided by conventional four-prong telephone jacks, is illustrated and described.

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Polarity Tester for Two Wire Serial Loop Communications System

Described is a polarity tester which may be used to test polarity and continuity of a two-wire serial loop communications system. An example of a two-wire serial loop in which the interfaces to the serial loop are provided by conventional four-prong telephone jacks, is illustrated and described.

The polarity tester includes two four-prong plugs. One of the plugs A includes the power source such as a battery E connected between the red R terminal and the green GN terminal of the A plug. The second plug B includes a light-emitting diode (LED) connected in series with a resistor R, between the black terminal BK and the yellow terminal Y of the second plug B. The serial loop may have a multiplicity of links and finding a polarity reversal without a tester would be time consuming and difficult.

The loop is tested starting at one point on the loop. The power plug is plugged into, for example, one of the terminations at the controller associated with the loop. The B plug is connected into the next interface to the loop to test the first link. The links are tested sequentially. A link is properly connected when the LED glows. Once a link is successfully connected, a shorting plug is inserted and the next point on the loop is checked by inserting the B tester at the next interface. This continues around the loop until the entire loop has been tested. The shorting plugs extend the tested sections to the next te...