Patent ID: 6173040
Filing Date: 2001-01-09
Classification: H04M

Abstract:
A telephone line state detecting device, that utilizes pulses generated by a telephone line to judge use state of said telephone line, said device being provided with a hardware detecting circuit, said hardware detecting circuit being provided with a first counter-amplifier, said first counter-amplifier having a first leg connected to a signal line of said telephone line, a second leg connected to a processing unit, and a third leg connected to a first leg of a second counter-amplifier, said second counter-amplifier having a third leg connected to parallel resistors, one of said resistors being connected in series to an algorithm amplifier, the other of said resistors being connected in series to a capacitor, said capacitor having an output end connected to an output end of said algorithm amplifier, said output end of said capacitor being connected to a first counter-gate, said first counter-gate having an output end connected to a second counter-gate, said second counter-gate having an output end connected to a display circuit that can display detection results.