Abstract: A circuit for detecting ringing signals on a telephone line in which the alternating voltage oscillations are converted to direct current pulses which are used to charge a first capacitor. Only signals of 14 hertz or above are sufficient to repetitively charge the first capacitor to a high enough voltage to open continuously a grounding circuit through a comparator, thus, allowing a second capacitor to charge up and open a second grounding circuit thus permitting current to flow to a suitable output. The output is used to activate lights on the telephone which lights are either flashed or winked by a unique resistance balanced solid state flash or wink generator.

Abstract: A miniature telephone jack with a molded housing especially adapted for use on printed circuit boards in which spring metal contacts grasp an inserted plug at the proper locations along its length with balanced, firm forces even though the contacts are all inserted from one side of the housing and have lugs extending therefrom through holes in the other side of the housing to make contact directly with a circuit board. The spring metal contacts include specially designed barbs which fit in slots molded on the sides of the housing to lock them in place.

Abstract: A system for electronically selecting and establishing test loop circuits between a remote test position and any of a large number of communication lines at an access location. Extensive logic circuits at the access end and the test end exchange information and display for the operator if the circuit is ready, if there has been a transmission error or component failure, if the circuits are busy, and other factors that affect the system thereby making the operator's task easier. Fail safe circuits prevent opening of telephone lines by access circuitry malfunctions.

Abstract: A molded electrical jack housing adapted for mounting directly on a printed circuit board in which the electrical contacts are all inserted from one side of the housing and have connection lugs extending through the opposite side of the housing and in which the electrical contacts are formed from spring metal material and shaped to have tabs which rest on special plateau areas formed in the housing.

Abstract: An intermediate patch cord for connecting together two other patch cords including a connecting wire with a standard plug receiving jack at each end. The plug receiving jack is formed from a pair of identical plastic molded housings and incorporates a pair of springable plug grasping fingers extending from one end to hold a standard plug in the jack housing.

Abstract: Telephone line testing equipment in which a series of alternating current tone pulses are transmitted from the central office along the lines to a sensing means placed at a remote point in the circuit. The sensing means receives the coded tone pulse sequence, decodes it to determine if the address is correct, and if so, what information is present, and then either connects or disconnects the remote equipment from the line or, in the alternative, connects suitable loopback testing circuits to the line.