Aircraft communication headset tester

Claim 1

A device for testing an aircraft communication headset having earphones provided with an earphone plug and a microphone provided with a microphone plug, said device comprising a housing, an earphone receptacle on said housing for receiving said earphone plug, a microphone receptacle on said housing for receiving said microphone plug, a multi-position function selector switch within said housing movable from an off position to a self-test position and to a talk-through position and to an earphone impedance test position, means on said housing for moving said selector switch to said positions, normally open self-test switch means within said housing, means on said housing for closing said self-test switch means, a volume display on said housing, first circuit means within said housing for coupling said microphone receptacle to said volume display, energizable indicator means on said housing, an oscillator within said housing, means operative in the self-test and earphone impedance test positions of said selector switch for deriving a voltage of a predetermined magnitude from said oscillator, a variable impedance in said housing, means for coupling said predetermined magnitude voltage to said variable impedance, a second impedance in said housing, said variable impedance having a common terminal with both said earphone receptacle and said second impedance, first means responsive to closing of said self-test switch means with said selector switch in its self-test position for applying said oscillator output to said first circuit means, second means responsive to closing of said self-test switch means with said selector switch in its self-test position for connecting said variable impedance and said second impedance in a first voltage divider circuit to provide a self-test voltage at said common terminal, means responsive to said selector switch in its earphone impedance-test position for connecting earphones plugged into said earphone receptacle in a second voltage divider circuit with said variable impedance to provide an impedance-test voltage at said common terminal, and means responsive to said self-test voltage and to said impedance-test voltage for energizing said indicator means when said device is functioning correctly and when said earphone impedance is correct. said first impedance having a terminal common to said second impedance and to said earphone receptacle, indicator means connected to said common terminal, means responsive to the selector switch in its self-test position for producing a first voltage at said common terminal, means responsive to said first voltage for causing said indicator means to indicate whether said device is functioning properly, means responsive to the selector switch in earphone impedance testing position for producing a second voltage at said common terminal and means responsive to said second voltage for causing said indicator means to indicate whether the impedance of earphones plugged into said receptacle falls within a predetermined range of values.

Claim 2

A device for testing an aircraft communication headset having earphones provided with an earphone plug and a microphone provided with a microphone plug, said device comprising a housing, an earphone receptacle on said housing for receiving said earphone plug, a microphone receptacle on said housing for receiving said microphone plug, a multi-position function selector switch within said housing movable from an off position to a self-test position and to a talk-through position and to an earphone impedance test position, means on said housing for moving said selector switch to said positions, normally open self-test switch means within said housing, means on said housing for closing said self-test switch means, a volume display on said housing, first circuit means within said housing for coupling said microphone receptacle to said volume display, energizable indicator means on said housing, an oscillator within said housing, means operative in the self-test and earphone impedance test positions of said selector switch for deriving a voltage of a predetermined magnitude from said oscillator, a variable impedance in said housing, means for coupling said predetermined magnitude voltage to said variable impedance, a second impedance in said housing, said variable impedance having a common terminal with both said earphone receptacle and said second impedance, first means responsive to closing of said self-test switch means with said selector switch in its self-test position for applying said oscillator output to said first circuit means, second means responsive to closing of said self-test switch means with said selector switch in its self-test position for connecting said variable impedance and said second impedance in a first voltage divider circuit to provide a self-test voltage at said common terminal, means responsive to said selector switch in its earphone impedance-test position for connecting earphones plugged into said earphone receptacle in a second voltage divider circuit with said variable impedance to provide an impedance-test voltage at said common terminal, and means responsive to said self-test voltage and to said impedance-test voltage for energizing said indicator means when said device is functioning correctly and when said earphone impedance is correct. said first impedance having a terminal common to said second impedance and to said earphone receptacle, indicator means connected to said common terminal, means responsive to the selector switch in its self-test position for producing a first voltage at said common terminal, means responsive to said first voltage for causing said indicator means to indicate whether said device is functioning properly, means responsive to the selector switch in earphone impedance testing position for producing a second voltage at said common terminal and means responsive to said second voltage for causing said indicator means to indicate whether the impedance of earphones plugged into said receptacle falls within a predetermined range of values.

Claim 7

A device for testing an aircraft communication headset having earphones provided with an earphone plug including in combination, a casing, an earphone receptacle on said casing for receiving said earphone plug, a multi-position function selector switch within said casing movable to a self-test position and to an earphone impedance testing position, normally open self-test switch means within said casing, means on said casing for closing said self-test switch means, an oscillator within said casing, a first impedance within said casing, a second impedance within said casing, means responsive to closing of said self-test switch means and to said selector switch in its self-test position for connecting said first and second impedances in series between said oscillator and ground, means responsive to said selector switch in said earphone testing position for connecting said first impedance and said earphone receptacle in series between said oscillator and ground, said first impedance having a terminal common to said second impedance and to said earphone receptacle, indicator means connected to said common terminal, means responsive to the selector switch in its self-test position for producing a first voltage at said common terminal, means responsive to said first voltage for causing said indicator means to indicate whether said device is functioning properly, means responsive to the selector switch in earphone impedance testing position for producing a second voltage at said common terminal and means responsive to said second voltage for causing said indicator means to indicate whether the impedance of earphones plugged into said receptacle falls within a predetermined range of values.

Claim 8

A device for testing an aircraft communication headset having earphones provided with an earphone plug including in combination, a casing, an earphone receptacle on said casing for receiving said earphone plug, a multi-position function selector switch within said casing movable to a self-test position and to an earphone impedance testing position, normally open self-test switch means within said casing, means on said casing for closing said self-test switch means, an oscillator within said casing, a first impedance within said casing, a second impedance within said casing, means responsive to closing of said self-test switch means and to said selector switch in its self-test position for connecting said first and second impedances in series between said oscillator and ground, means responsive to said selector switch in said earphone testing position for connecting said first impedance and said earphone receptacle in series between said oscillator and ground, said first impedance having a terminal common to said second impedance and to said earphone receptacle, indicator means connected to said common terminal, means responsive to the selector switch in its self-test position for producing a first voltage at said common terminal, means responsive to said first voltage for causing said indicator means to indicate whether said device is functioning properly, means responsive to the selector switch in earphone impedance testing position for producing a second voltage at said common terminal and means responsive to said second voltage for causing said indicator means to indicate whether the impedance of earphones plugged into said receptacle falls within a predetermined range of values.