Abstract: A mobile radio device is disclosed that includes a microphone and a loudspeaker, wherein said loudspeaker (LP) is adapted for sound reproduction in the hands-free mode and/or for call signaling. The device is provided with a unit to acoustically measure the distance between the loudspeaker and an obstacle, the distance measured by measuring the propagation time of the test sound. The call signal volume or hands-free volume is controlled in accordance with the propagation time measured. Additionally, the output volume on the loudspeaker can be controlled in accordance with the measured volume of the reflected test sound.

Abstract: A speech control is provided for a telephone station and provides, dependent upon speech direction, the transmitting channel or the receiving channel being attenuated or the receiving channel being attenuated or the receiving channel or the transmitting channel being de-attenuated with a structure which is as simple as possible to manufacture with, inexpensive, non-critical components. A potentiometer is provided in each channel for setting the volume and the potentiometers are simultaneously and symmetrically operated with a single operating element. The potentiometers, dependent on speech direction, determined by a speech analyzer, are simultaneously shorted or simultaneously activated. The shorting in the transmission channel has a de-attenuating effect and has an attenuating effect in the receiving channel. When the potentiometers are in the activated condition, they cause the opposite effect.