Systems and methods for reducing squealing or feedback on amplified telephones are disclosed. The telephone system generally includes a receiver in communication with a receive signal path, a transmitter in communication with a transmit signal path, a receiver gain detector configured to detect a receiver gain on the receive signal path, and a controller configured to operate the telephone system in full duplex when the receiver gain is approximately less than a receiver stability level and to operate the telephone system in adaptive duplex when the receiver gain is approximately above the receiver stability level. The adaptive duplex mode is such that an adaptive attenuation level alternately applied on the receive and transmit signal paths is dependent upon the level by which the receiver gain exceeds the receiver stability level.