US 4,446,338 A · Telephone lines status sensor

Abstract

A lines status sensor provides for monitoring of the operating status of one or more telephone lines at an associated telephone station apparatus. The lines status sensor includes a translation circuit being responsive to potential differences appearing across the telephone line, for generating a voltage signal of corresponding polarity in relation to a reference voltage. A voltage divider circuit provides the reference voltage in addition to a first limit voltage being of a more negative potential than the reference voltage, and a second limit voltage being more positive than the reference voltage. A detection circuit is responsive to the first and second limit voltages such that when the potential of the output voltage from the translation circuit is within a range as defined by the first and second limit voltages, an output signal of the detection circuit is of one binary state thereby indicating an OFF HOOK status of the telephone line, and when the potential is outside of the range the output signal is of another binary state thereby indicating an ON HOOK status of the telephone line. In a variation of the line status sensor a wider range is useful for detecting the presence of ringing signals on the telephone line.

Claims14

Dependent claims

A line status sensor for use in a telephone station apparatus including a pair of line terminals for connection to tip and ring leads of a telephone line, the line status sensor comprising:

first and second power terminals for connection across a power source;
first means being connected across the first and second power terminals, for generating a reference voltage, and first and second limit voltages of negative and positive polarities respectively in relation to the reference voltage;
a translation circuit being responsive to forward and reverse potential differences appearing across the line terminals and to the reference voltage, for generating voltage signals of corresponding polarity in relation to the reference voltage;
a detection circuit for generating an output signal being of one binary state in response to the voltage signal being outside of a range defined in relation to the first and second limit voltages, and for generating the output signal being of another binary state in response to the voltage signal being within said defined range, whereby said output signal is indicative of conditions of the telephone line.

1 more element

A lines status sensor for use in a telephone station apparatus including pairs of line terminals, each pair being for connection to tip and ring leads of one of a plurality of telephone lines, the lines status sensor comprising:

first and second power terminals for connection across a power source;
first means being connected across the first and second power terminals, for generating a reference voltage and first and second limit voltages of negative and positive polarities respectively in relation to the reference voltage;
a plurality of translation circuits, each translation circuit being responsive to forward and reverse potential differences appearing across a corresponding pair of the line terminals and to the reference voltage, for generating a correspondingly proportional voltage signal of corresponding polarity in relation to the reference voltage;
a plurality of detection circuits, each detection circuit being for generating an output signal being of one binary state in response to the voltage signal from a corresponding one of the translation circuits being outside of a range defined in relation to the first and second limit signals, and being for generating the output signal being of another binary state in response to said voltage signal being within said defined range, whereby said output signal is of ON HOOK and OFF HOOK condition of the telephone line connected with the corresponding pair of line terminals.

1 more element

Dependencies are inferred from the claim text.

Telephone lines status sensor

Life of this patent

Telephone lines status sensor

Life of this patent

Abstract

Claims14