A telephone apparatus comprises a first audio input device, a second audio input
device, a first audio output device, and a second audio output device. The telephone
apparatus is operative to couple the first audio input device and the first audio
output device to a first telephone line. In response to a first signal, the coupling
between the first audio input device and the first telephone line is modified,
and the second audio input device and the second audio output device are coupled
to a second telephone line.