DETAILED DESCRIPTION OF THE INVENTION Depicted in FIG.
1 is a power source unit 20 of the invention for energizing a portion of a four wire pair telephone signal distribution network for test purposes.
The unit 20 includes a standard, "modular" 8 "pin" telephone plug 22 attached at an end of an eight wire cable 24 connected with a box 25.
The box 25 contains a 3-volt transistor battery 26 (depicted in phantom), circuit connections (represented diagrammatically by the phantom box 28) between the two poles of the battery 26 and eight wires of the cable 24, a battery test button 29 and battery status light 30.
Referring to FIG.
1a, the connector 22 is a standard four wire pair modular telephone plug, such as an AMP-554112-1 and includes eight individual, exposed metallic conductors 23 electrically and physically connected with the eight individual wires 27 of the single line cable 24.
Standard numbering of the eight individual wires of the line is indicated by the numbers 1-8 on the right side of the figure.
The four wire pairs of the line are identified as A-D on the left side of the figure.
FIG.
2 depicts an exemplary preferred circuit connection between the eight wires 27 (wire pairs A-D) with the battery 26.
Individual wire pairs A-D are connected in an asymmetric manner so as to provide polarity as well as continuity information when used with the read-out unit of FIGS.
3-4.
In particular, odd numbered wire 3 and even numbered wire 4 of the wire pair B are connected with the positive and negative poles, respectively, of the battery 26 while the odd numbered wires (1, 5, and 7) and the even numbered wires (2, 6, and 8), of the remaining pairs A, C, and D are connected to the negative and positive poles, respectively.
The purpose of this asymmetric arrangement is to provide different polarity states in the wire pairs of each individual line.
If, for any reason, the wire pairs are rearranged, particularly as might occur by an unseen twist in a trunk cable or improper attachment of the read-out unit, a characteristic indication will result
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