Multipurpose headset amplifier

Claim 1

A multipurpose headset amplifier device for the connection of a headset to be attached to a telephone instrument and comprising a housing with an ascending, thready holder for a headset and connection jacks for the headset, said housing having at the upper side comprises manual operating members for the adjustment of the device, and which housing at the underside comprises manual controls for the adaption of a headset to the impedance and signal level of any telephone instrument, and wherein the amplifier device comprises amplifier and adjustment circuits for the headset and an internal power supply source and a jack for an external power supply source, in that the amplifier circuit from the headset microphone to the telephone instrument comprises a preamplifier, an electronic microphone switch circuit, a voice-activated gain switch, a manually adjustable amplifier and a galvanic separation circuit comprising a transformer, and a carbon microphone amplifier circuit for the shunt coupling of the adjustable amplifier and the galvanic separation circuit, and in that the amplifier circuit from the telephone instrument to the headset sound reproducer comprises a galvanic separation circuit having impedance control members, a volume control circuit, a preamplifier circuit, a threshold value-adjustable adjustment circuit and an output amplifier.