AU625373B2 - Audio lead tester - Google Patents

Description

The Commissioner of Patents

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41; t I APPLICANT: MICHAEL PARIS KYRANNIS

NUMBER:

FILING DATE: Form COMMONWEALTH OF AUSTRALIA The Patents AclI 1952 COMPLETE SPECIFICATION FOR AN INVENTION ENITTLED: AUDIO LEAD TESTER Tho following s tatement. is a full description of thLs Inven lion, including the best method of performing it known to me/us:

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-UC L~ This invention relates to an audio lead tester and, specifically to a tester which can provide a visual display of the wiring configuration of an audio or other cable.

Audio cables normally have three conductors and it is often essential to know which conductors are on which contact on a terminating plug or socket.

It is also to be appreciated that equipment uses various types of termination such as, for example, 3 pin Cannon and 1/4 inch, two and three connector plugs, phone plugs and their sockets and jacks and, on occasions, RCA plugs, DIN plugs and other forms of plugs.

sit' a; S Previously it has been possible to ascertain the actual 4 4 4 connections on a plug either by doing a simple continuity check, using a multimeter or the like, or there have been proposed various very expensive items which can provide the information automatically.

The object of the present invention is to provide a device which can simply and readily provide this information.

A lead tester comprising at least one input device to which the conductors of a lead to be tested can be connected and at least one output to which the conductors can be connected each conductor being connected at one of its ends to the input and at ;,P1/SPEC/KYRANNIS.SPC/30 March 1992 23 3 2A the other of each respective end to the corresponding output of the tester, a display matrix, the sides of which are equal to the number of conductors being tested, row drivers in association with either the input' or the output, column drivers in association with the output or the input and means whereby signals can be passed to the row drivers and column drivers to provide an indication of the connection between any particular input conductor and any particular output conductor.

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0& 01 Mr 19 ga C^^f;l/SPEC/KYRANNIS.SPC/30 March 193^ 4 i 7 r7--.

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-psn~*~ In order that the invention may be more readily understood, reference will be made to the accompanying drawing', in which:- Fig. 1 is a block diagram of the device of the invention; and Fig. 2 is one particular circuit which can be used with the invention.

Physically, the device can be mounted in a relatively small box having on its surface an array of LED's in a matrix.

Where the device is to be used for testing audio cables, the LED's are in a S three by three matrix.

Located on the box there can be inputs and outputs.

0"oo It is preferred that the inputs can comprise a number of parallel inputs .which correspond to the most used connections for the cables to be tested.

The types of plugs and sockets or jacks commonly used are set out hereinbefore and any combination of these could be provided. The types set out for specific application are only exemplary and there may be alternative forms of connectors provideu.

The outputs can have the same or complementary connectors, although it will be appreciated that, normally, there will be sockets rather than plugs as plugged cables are normally terminated with plugs at each end.

There is also provided a test switch which can simply caise the device to operate and there may also be a further test switch which causes all of the -3- Kyrannis/75/May89 LED's to ignite, thus acting as a check on the LED's.

Referring to the block diagram of Fig. it will be seen that the three inputs are connected to row drivers and the three outputs to column drivers.

This means that each of the inputs can drive one of the rows of the LED and, when the input receives a high logic level the respective row is enabled.

Associated with the three outputs there is an astable oscillator which o° drives a decoder which provides a signal having a particular pulse to each o' of the outputs and to each of the column drivers.

Shown on the block diagram there are the three different outputs from the output decoder and it will be appreciated that these are fed, not only to the column drivers, but also to -the inputs, by way of the cable being tested.

The arrangement is such that, when any of the row drivers is high, the appropriate LED's are enabled and, if, at the same time, any of the column drivers is high, then the associated LED will light.

This will provide an indication that the particular output is connected to the particular input.

It can be seen then that, when the device is operating, there will normally be three LED's ignited and each of these shows the input and the output associated th ere with.

Even should two of the cables be shorted, there will still be an indication, but this will indicate that there is a short circuit, as the indication will be Ky rannis/75/May9 -4- I Ky ra nni s/ 7 5/May 89 spurious and normally will comprise more than three LED's igniting and, if any of the conductors is open circuit, then there will normally only be two LED's alight indicating this situation.

Referring to Fig. 2 IC2e together with RI and Cl form an astable oscillator which is used to clock ICI, the "one of three" decoder.

This decoder supplies a "high" level alternate pulse to the three outputs and is also used to "turn on" Q1-Q3 which are the column drivers.

4'a 4 "4 DI-D3 provide protection for IC1 against short circuits between any output.

The three inputs are coupled to TCa-ICc which act as level detectors and in turn "turn on" Q4-Q6, the row drivers.

R14-R16 provide current limiting for the LED matrix.

D4-D6 form part of the "lamp test" facility by providing input isolation.

When the "lamp test" input is connected to +Vcc via an optional switch, all LED's should light.

As illustrated in Fig. 2 the power supply for the device is simply a standard 9 volt battery and diode D7 is incorporated to protect the device from reverse polarity in the battery.

If required I can provide a battery charging circuit so that a rechargeable battery can be used to obviate the necessity of changing batteries.

Also, should this be required I could build in a power supply which could enable the device to run from mains power and any such power supply may Kyrann is/75)/May89 'L A

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have associated therewith a battery charging circuit so as to be able to both provide mains operation and at the same time to maintain a battery in a charged condition.

LEDI-LED9 form the three by three LED matrix.

It will be appreciated that, whilst I have described one particular circuit, this is only exemplary, the invention being more particularly shown in the block diagram as there may be a number of different ways to provide a circuit which provides the end result.

It will be seen that in a small and compact piece of equipment most types of audio cables or other three conductor cables can be readily checked to find the form of connection.

I t Ky rann is/75/May89

Claims (6)

1. A lead tester comprising at least one input device to which the conductors of a'lead to be tested can be connected and at least one output to which the conductors can be connected each conductor being connected at one of its ends to the input and at the other of each respective end to the corresponding output of the tester, a display matrix, the sides of which are equal to the number of conductors being tested, row drivers in association with either the input or the output, column drivers in association with the output or the input and means whereby signals can be passed to the row drivers and column drivers to provide an indication of the connection between any particular input conductor and i any particular output conductor.

2. A lead tester as claimed in claim 1 wherein the display matrix consists of a number of display members which are adapted to display when they are enabled from the row drivers and when the appropriate column driver is active.

3. A lead tester as claimed in claim 1 wherein the display matrix is a matrix light of emitting diodes.

4. A lead tester as claimed in any preceding claim wherein the column drivers are associated with an oscillator which controls a decoder which provides a predetermined signal to WP51/SPEC/KYRANNIS.SPC/30 March 1992 the column drivers and when a particular column driver is enabled and the required code is passed thereto, the associated display member is illuminated.

A lead tester as claimed in any preceding claim wherein there is a circuit which can enable each of the row drivers and actuate the column drivers so that the operation of each of the display members of the matrix can be ascertained.

6. A lead tester substantially as hereinbefore described with reference to the accompanying drawings. DATED this 30th day of March, 1992 MICHAEL PARIS KYRANNIS By His Patent Attorneys A. TATLOCK ASSOCIATES T WP51/SPEC/KYRANNIS.SPC/30 March 1992