AMPLIFIER ARRANGEMENT FOR TELEPHONE INSTRUMENT

An amplifier arrangement for controlling the output level of an amplifier used in a two-wire line telephone system comprises an attenuation circuit, a memory circuit, an integration circuit and a test device. The output level of the amplifier is tested by the test device and if the output level is too high activates the integration circuit. When the output voltage of the integration circuit exceeds a certain value the memory circuit changes state to (1) activate the attenuation circuit so that the output level of the amplifier is decreased, and (2) re-set the integration circuit. The memory circuit remains in its changed state until the direct voltage level of the two-wire line is essentially changed in which case the memory circuit is re-set to the original state and the attenuation circuit is no longer activated and the integration circuit may again be started by the test device.