Abstract: A circuit arrangement converts signals and information between analog junction lines and digital terminal devices in communications exchanges. A decentralized control device is provided in order to process and pass on switching criteria and codes received and sent to the respective analog junction line, inside and outside the audio frequency band, the circuit arrangement including a plurality of line interfaces, each coupled directly to a respective one of the decentralized control devices, for the switching criteria and codes to be exchanged outside of the audio frequency. At least one digital signal processor is provided for processing the codes to be exchanged within the audio frequency band, the digital signal processor being looped in via a hybrid connection and converter in a speech path which cooperates with the control device.

Abstract: A process and apparatus for a voice controlled attenuation adjustment in telephone transmission circuits is disclosed. Signals in the sending and receiving directions are decomposed into sub-band signals in a set of frequency sub-bands. Each frequency sub-band is associated with an attenuation device for each direction of transmission. Depending on the level of activity in each direction in a particular sub-band, the attenuation values of the attenuation devices of that particular sub-band are adjusted. The sub-band signals are then recombined.