Selective blocking device for controlled use of telephone lines.

摘要

Selective blocking device for controlled use telephone lines that having aimed at preventing his first phone calls figure match any of the prohibited eats established in a previous programming; essentially it characterized in that it is formed from an electronic assembly comprising a power supply from the telephone line itself, a detector line off hook, a pulse sensor selection, a counter pulse circuit, a timer block and end detector cipher block control first figure connected to the detector line off-hook and the counter pulse circuit a control block of the first figure, a block of pleated programming and control circuit impedance telephone line, being, which in turn, receives the pulses of the detector block select pulses; with the particularity that the control block first digit, selectively activates the control circuit impedance depending on the association compared to the programming wiring block is connected to the counter circuit; having foreseen that the electronic assembly is connected in series with the telephone line itself, there being a switch for inhibiting device.