JPS63187460U - - Google Patents

Description

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of a response detection circuit device for a terminal on the other end of a telephone according to this invention, Fig. 2 is a block diagram showing another embodiment according to this invention, and Fig. 3 is a block diagram showing a conventional implementation. FIG. 2 is a block diagram showing an example. 1: Hook switch, 2: Current direction detector, 3
: Diode bridge for polarity reversal prevention, 5: Interface, 6: Positive polarity change detector and trigger pulse generator, 7: Negative polarity change detector and trigger pulse generator, 8, 22: OR circuit , 9: Reset circuit, 10: Set/Reset/
Flip-flop circuit, 11, 15, 16: resistor, 12: transistor, 13: dial mode selection switch, 14: time constant circuit, 17: mode switching line, 20: tone ringer circuit, 21: hook-off delay reset Circuit, 23: Power-on reset circuit, 24: Power supply circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] In a detection circuit of a telephone that detects that the other party's terminal has responded, the circuit that detects that the other party's terminal has responded is configured such that the current direction of the telephone line changes from the positive direction to the negative direction. a first detection circuit that detects a change in , and a second detection circuit that detects a change from a negative direction to a positive direction, and the connection to the telephone terminal of the telephone is configured to be independent of polarity. A response detection circuit for a terminal at the other end of a telephone set.