2741767-A1 cites 5 patents.
The device includes a management processing interface (110) which controls function access to a telephone bus line (112) connecting two telephone terminals (P1,P2). There are two processing modes, manual and automatic. The processing interface interacts with telephone bus surveillance monitors (120,121) and releases information when the line is free. A tone generator (140) provides sound information (165) and a display generator (160) provides visual information.