The 7150 relay constantly monitors telephone line DC voltage detecting shorted or open telephone lines. If the phone line is cut or shorted, after a 40 to 60 second delay, it will activate an LED indicator light and provide a N/0-N/C output. Its Form C relay contacts can be used to activate a local alarm or a backup means of communication to a central station such as long range R.F.
The 7150's high impedance prevents interference with normal telephone operation. Its relay contacts will reset automatically when phone line voltage is restored, but the LED will remain on until the reset button is pressed.
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