Multi-protocol modem for analog two-wire telephone line

The system includes a transmitting device (1) and a reception device for transmitting and receiving digital data in an analog telephone system. The transmitting device includes a first coding arrangement (11) for encoding and modulating the digital data on a predetermined carrier frequency in the range of 0 to 4 kHz. The reception device includes a first decoder arrangement for demodulating and decoding a received signal with the predetermined carrier frequency. The transmitting device includes a second coding arrangement (12) for encoding and modulating digital data on a second predetermined carrier frequency in the range above 4 kHz. A combining arrangement (13) combines the signals produced through the first and the second coding arrangement. The reception arrangement comprises a separating arrangement (28) for dividing a received analog signal into a first signal with the first predetermined carrier frequency and a second signal with the second predetermined carrier frequency. A second decoder arrangement is provided for demodulating and decoding the received signal with the second predetermined carrier frequency to provide a digital reception signal. Multi-Modemprotokoll mit Datenraten von M x 33600 bit/s und höher zur Nutzung auf analogen Zweidrahtleitungen. DOLLAR A Bei der vorliegenden Erfindung handelt es sich um ein System zum Senden und Empfangen von digitalen Daten in einem analogen Fernsprechnetz. DOLLAR A Die Daten können dabei sowohl in einem herkömmlichen analogen Fernsprechnetz im Frequenzbereich von 0 bis 4 kHz als auch in einem analogen Fernsprechnetz mit einer Bandbreite von mehr als 4 kHz übertragen werden.