Abstract: An improved telephone protector module for individual subscriber circuits incorporating, in addition to heat sensitive means for grounding outside plant tip and ring currents, switch means for simultaneously opening the tip and ring circuits leading to central office or PBX equipment when excessive current is detected. The switch means is normally in closed position when the heat sensitive means is in unfired condition.

Abstract: A test cord including a plug suitable for testing individual subscriber circuits, terminals of which appear on a protector block mounted on a telephone main frame. The cord includes a terminal plug adapted to engage the exposed end of a telephone circuit protector module to enter recesses therein to provide electrical conductivity therebetween. The plug and module are provided with corresponding detenting means for maintaining the same in engaged condition, and corresponding guiding means to prevent such engagement in an improper mutual orientation.

Abstract: A line voltage surge protecting device for telephone systems which normally include means for grounding excessive currents caused by lightening and the like. The device includes a gaseous discharge element which becomes conductive when the voltage in the line being protected momentarily exceeds a predetermined value to conduct current to a source of ground potential. A temperature sensitive element responsive to heat generated by the gaseous discharge device during prolonged excessive current serves to short the gaseous discharge element to ground. The temperature sensitive element includes means resiliently biasing the gaseous element for movement serving to short the same. A soldered retaining means opposes such movement, and heat developed in the gaseous discharge device is transmitted to the soldered means by conduction to melt the solder to permit the shorting action to occur.