Voice modem protocol for uninterrupted data connection

• Main Author: YU JINGUO
• Format: Patent
• Language: English
• Published: 08.02.2007
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

A back-up solution is presented for a DSL modem that guarantees essentially uninterrupted data connections in the event of a failure in the DSL connection. When a DSL data connection fails, e.g., due to changes of the local loop characteristics in the high frequency band, a voice-band modem is used in conjunction with an amplitude modulator/demodulator to keep the data connection uninterrupted by shifting the voice-band modem signal up to DSL frequencies, transmitting the data at this higher frequency over the local loop between the subscriber and a DSLAM, and then shifting the voice-band modem signal back to a "normal" frequency and demodulating this signal using the voice-band modem before it enters the data network. Since the frequency band used is at a frequency higher than that of voice communications, the subscriber can continue to use the local loop to conduct voice communications or any other communications that require use of the voice band frequencies, such as facsimile and V. series modem communications.