IE42567B1 - An apparatus for checking of the pairing of wires - Google Patents

Abstract

1502043 Testing insulated conductors COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS CIT-ALCATEL SA 31 March 1976 [16 April 1975] 12931/76 Heading G1U In detecting incorrect pairing of twisted pairs in a multi-wire telecommunications cable, a signal is injected into successive ones of the first wires of the pairs, and signals from the second wires of the pairs due to induction are detected. The cable has pairs ai, axi;...an, axn at one end and pairs bl, bxl;... bn, bxn at the other. These are connected to male multi-way connectors, which fit female connectors on the apparatus front-panel, Fig.2 (not shown). This connects ai ... an ie the first wires of the n pairs to the outputs of a demulti-plexer DM, and the corresponding second wires at the other cable end bx1... hxn to detector D1... Dn. A 10Hz oscillator 01 feeds a counter CT whose outputs provide the address inputs to the demultiplexer DM, which thus sequentially directs 2MHz signals from oscillator 02 to successive first wires ai ... an. The counter CT outputs are also de-coded D.C. to illuminate one of lamps L1-Ln on the front panel via outputs Sl-Sn, corresponding to the energized wire. Whichever second wire is twisted with the energized first wire provides an induced voltage to one of the detectors D1-Dn. That detector provides an output Sx1 ... Sxn to illuminate a second lamp on the front panel. These lamps are arranged, such that correctly paired wires illuminate lamps side-by-side, Figs.2, 3B, 4B, 5B, 5C (not shown). A comparator CP compares the de-coder D.C. output and the detector outputs and if these do not correspond to correctly paired wires, a low output to NOR-gate PN causes that gate to block oscillator 01, thus stopping further stepping, and the front-panel lamps stay illuminated to indicate a fault. The stepping is recommenced by operation of a push-button BD which actuates a monostable BM to give a high output, thus removing the blocking signal Ebto the oscillator.

Description

This invent, ion concerns apparatus for checking tlie pairing of conducting wires, especially for wires twisted in pairs in a cable.

Such cables are currently used in telecommunications, especially in telephony, where symmetrical input and output equipment is linked to cables of wires twisted in pairs, a large number of pairs being housed in the same cable.

At the moment when cable ends are connected to 2q connector tags, wires of different pairs can be accidentally cabled in the wrong order. As a matter of fact the twists are very loose and consequently the paired wires are often untwisted at the cable ends and cabling errors may occur between wires belonging to different pairs. j_5 These errors lead to interference coupling between the incorrectly cabled pairs. When, for example, Ihe said pairs transmit speech currents, this interference coupling generates crosstalk which is detrimental to the quality of reception of conversations at telephone set receiver level.

A great percentage of wire inversions on connector tags is detected by continuity test between corresponding cable end connector tags.

However, one wire of a pair may happen to be connected to a connector tag usually assigned to another pair and vice versa, and consequently this defect may affect symmetrically the corresponding tags of the two connectors.

Xn this case the continuity test is ineffective to detect the pairing defect since although the continuity of wires between corresponding tags is correct, the paired wires obtained that way are incorrectly paired.

The aim of this invention is to provide an automatic apparatus for checking the pairing of wires at cable ends for the identification of wires which are incorrectly paired and which cannot be detected by the continuity test.

The present invention provides an apparatus for checking the correspondence between the arrangement of wires in pairs at at least one end of a cable (end pairs) with the disposition of the same wires along the cable in pairs that are twisted together (twisted pairs), the apparatus comprising: means for scanning successive first wires of the end pairs of a cable, means for injecting a signal into the successively scanned first wires, means for detecting the signal as induced at second wires of the end pairs, and means for providing a fault indication when the induced signal does not appear at the second wire which is arranged as an end pair with the first wire into which the signal is being injected.

Preferably, the ends of the second wires of each pair not subjected to the high frequency signal injection are each connected to a detector of signals induced by said highfrequency signals.

The apparatus may include two sets of lamps, one set indicates the injected wires, the other indicates the wires induced by said high-frequency signals. If the pairing of a pair is not correct, a comparator stops the clock and the wires concerned remain permanently indicated.

The invention will now be described in more detail, by 5 way of example only with reference to the accompanying drawings, in which:Figure 1 is a block diagram of an apparatus embodying the invention; Figure 2 illustrates a front view of the apparatus; Figure 3A gives an example of incorrect pairing of paired wires in succession; Figure 3B shows the state of the lamps after the pairing check has been executed on the first connector tag pairs cabled according to figure 3A; Figure 4A is a cabling corrective phase once the pairing defect on the first pairs of tags has been rectified; Figure 4B shows the state of the lamps after the pairing checking has been carried out on the second connector tag pairs cabled according to figure 4A; Figure 5A illustrates the correctly paired connectors; and Figures 5B and 5C respectively show the state of the lamps after the pairing check has been carried out on the first and on the second connector tag pairs cabled according to figure 5A.

The apparatus shown in figure 1 is composed of a first oscillator 01 sending low-frequency clock signals (10 hertz for example) to the clock input EC of binary counter CT, the outputs of which are connected on one hand to address inputs of a demultiplexer DM having n outputs al, a2,...an, and on the other hand to the inputs of a decoder DC having n outputs Sl,S2, ....Sn. A second oscillator 02 emits high frequency signals (2 megahertz for example) to data input Ed of the demultiplexer DM. 4256 Outputs SI, S2,.,..Sn of the decoder DC are respectively connected to inputs EA1, EA2,....EAn of a comparator CP, the output of which is connected to the first input of NOR gate PN, the output of which is connected to a blocking input Eb of the first oscillator 01.

Detectors Dl, D2,...Dn having respective inputs bxl, bx2,...bxn and respective outputs which are connected, on one hand, to outputs sxl, sx2 , xn of the apparatus and, on the other hand, to inputs EBX1, EBX2...EBXn of corresponding order to comparator CP.

The second input of the NOR gate PN is connected to the output of a monostable flip-flop BM, the input of which is connected to a non-locking key BD allowing the inhibition of the blocking control of oscillator 01. A make contact of said key is connected to one side of a powersupply through a resistance R.

Figure 2 illustrates the front view of the apparatus which comprises, on one hand, two female connector tags CFA, CFB designed to receive the cable end connectors, and which shows, on the other hand, a display of lamps Ll to Ln and LX1 to LXn indicating the pairing of paired wires. The display facilitates the suspension of the check on correct pairing and the sorting out of tags to which the indicated faulty wires are connected.

Outputs al, a2,.:.an of the demultiplexer are connected to the corresponding female tags Al, A2,...An of the female connector CFA indicated in figure 2. Inputs b 1, b 2,... bxn of detectors Dl, D2,...Dn are connected to the corresponding female tags BI, B2,...Bn of the female connectors CFB shown in Figure 2.

Outputs SI, S2,...Sn of the decoder DC are connected to corresponding lamps Ll, L2,...Ln and outputs Sxl, Sx2,... y S n of the detectors Dl, D2,...Dn are connected to corres5 567 ponding lamps Lxl, Lx2.. .Lxn placed on the apparatus panel (Figure 2).

The pairing tests of a cable whose ends are connected to male connectors CMA and CMB (figure 5A) need a preliminary plugging in of said male connectors into female connectors CFA and CFB.

Hereafter the functioning of the apparatus will be explained; for that purpose, the checking of a cable like the one shown in figure 3A having a pairing defect will be used as an example. Ends al-aXl, a2-aX2. and bl-bxl, b2-bx2... are meant to be connected to parts All, A22... and Bll, B22,... through connectors CMA and CMB.

As the cable connectors have been plugged in onto the apparatus a return to zero key (not shown on the diagram figure 1) is put into action and stops the positioning control at step 0 of binary counter CT which moves to step 1 where it remains positioned during the period of low frequency signal of oscillator 01. The binary counter selects via the binary address inputs of the demultiplexer DM, output al of the latter.

Through data input Ed of the demultiplexer DM, the oscillator 02 sends high-frequency signals to the selected output al. These signals are then injected to wire fl of the cable (figure 3A) and induced to wire fx2 paired to wire fl.

Wire fx2 being connected to tag bx2 of connector CMB, induced signals arrive on input bx2 of detector D2 (figure 1), and through output Sx2, switch on the corresponding lamp Lx2 in the panel shown in figure 2.

Decoder DC decodes in decimal digit the binary digit 1 representative of step 1 of counter CT, which causes output SI of said decoder to be power-fed and corresponding lamp Ll to be switched on.

Monostable flip-flop BM is at rest and sends a state 0 to an input of gate PN. Outputs Si and S 2 being active comparator CP has its two non corresponding inputs EA1 and EA2 energized and, consequently, sends a state 0 to gate PN whose output indicates a blocking state 1 to input Eb of oscillator 01; counter CT remains on step 1 and lamps Ll and Lx2 remain switched on.

X X Lamp L 2 being switched on instead of lamp L 1, the operator comes to the conclusion that the wire connected to tags bx2 and ax2 should be connected to tags bxl and axl.

He can either note the pairing defect and check the following wires, or proceed immediately with the elimination of the defect.

In the first case, after he has noted the defect, he operates the non-locking key BD; as a consequence, monostable flip-flop BM is triggered and sends a state 1 impulse to gate Pn whose output changes to state 0, causing the blocking control of oscillator 01 to be stopped during a signal period. Oscillator 01 starts again and counter CT advances onto the following step.

In the second case, he unplugs the connectors after having positioned the return to zero key to rest and proceeds with the cabling of wire fx2 to tags aXl and bxl as indicated in figure 4A.

The release of the return to zero key having caused the reset to zero of counter CT, this counter advances to step 1 and indicates, once more, point al when the control operation comes on again.

As indicated in figure 4A, high-frequency signals injected in al to wire fl are then induced to bxl, the former wire fx2 changing to fxl. These induced signals are X detected by detector Dl which switches on lamp L 1. Lamps Ll and LX1 are then switched on as shown in figure 5B, which means that the pair of wires corresponding to stop 1 of the counter is correctly paired. - 7 42567 Comparator CP having its corresponding inputs EAl and EBX1 energized does not send any blocking signal to input Eb of oscillator 01. Therefore, counter CT advances to step 2 selects output a2 of demultiplexer DM onto which oscillator 02 injects high-frequency signals.

Said signal arriving on wire 2, are induced to the wire connected to tags axl and bxl (figure 3A and 4A). Consequently, they are detected in bxl by detector DI and lamp LX1 switches on. Counter CT being at step 2, lamp L2 is switched on. Non corresponding inputs EA2 and EBX1 of comparators CP being energized, that comparator causes the blocking of oscillator 01 and the counter CP remains on step 2.

Lamp L 1 being switched on instead of lamp L 2, the operator comes to the conclusion that the ends of former wire fxl connected to tags axl and bxl must be disconnected from these and connected to tags ax2 and bX2, former wire fxl changingto fx2 as indicated in figure 5A which represents the correct pairing of the wires.

The correct pairing control of wires such as those indicated in figure 5A is revealed by the successive switching on of homologous lamps Ll-Lxl, L2-Lx2, etc.

Claims (13)

1. CLAIMS:1. An apparatus for checking the correspondence between the arrangement of wires in pairs at at least one end of a cable (end pairs) with the disposition of the same wires along the cable in pairs that are twisted together (twisted pairs), the apparatus comprising: means for scanning successive first wires of the end pairs of a cable, means for injecting a signal into the successively scanned first wires, means for detecting the signal as induced at second wires of the end pairs, and means for providing a fault indication when the induced signal does not appear at the second wire which is arranged as an end pair with the first Wire into which the signal is being injected.

2. An apparatus according to claim 1 wherein the means for scanning successive first wires comprises a low frequency clock driving a counter with outputs connected to a demultiplexer for connection to the first wires of a cable end.

3. An apparatus according to claim 2, wherein the outputs of the counter are connected to a decoder driving indicator lamps to indicate the number of the first wire being scanned.

4. An apparatus according to claim 2 or 3, wherein the means for injecting a signal into the first wires comprises a high-frequency signal oscillator connected to a data input of the demultiplexer.

5. An apparatus according to any previous claim including a multi-way connector half for connection to the end of a cable whose wires are arranged in end pairs by their connections to a mating connector half, the connector halves having mating first wire connections and mating second wire connections.

6. An apparatus according to claim 5, including two multi-way connector halves, one for each end of a cable having both ends equipped with mating connector halves.

7. An apparatus according to claim 6, wherein the signal is injected into first wire connections of one connector half and the means for detecting the induced signal is connected to the second wire connections of the other connector half.

8. An apparatus according to claim 5,6 or 7, wherein the means for detecting the induced signal includes a plurality of signal detectors, each connected to a corresponding one of the second wire connections.

9. An apparatus according to claim 8, wherein each detector is connected to a corresponding lamp which indicates when an induced signal is detected by the detector.

10. An apparatus according to claim 9 and to claim 3, wherein the means for providing a fault indication includes a comparator connected to the outputs of the detectors and to the outputs of the decoder and arranged to provide a fault indication when the said outputs do not correspond. 10

11. An apparatus according to claim 10, wherein the fault indication comprises means for stopping the clock to provide an unchanging indication of the number of the first wire being scanned and the second wire actually 5 receiving the induced signal,

12. An apparatus according to claim 11, including manual override means for restarting the clock from where it s topped.

13. An apparatus for checking the correspondence 10 between the arrangement of wires in pairs at at least one end of a cable (end pairs) with the disposition of the same wires along the cable in pairs that are twisted together (twisted pairs), substantially as herein described with reference to the accompanying drawings.