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AssigneeCisco Technology, Inc.
InventorsDavid Qi, Yan Wang, Timothy Wade
Estimating the term…
High compression rate codecs in gateways servicing Voice-over-Internet Protocol (VoIP) and Voice Band Data (VBD) calls distort modem/fax Answer Back Tones (e.g., 2100 Hz), which may lead to signal distortion and call hang-ups. To prevent such occurrences, a method or corresponding apparatus forces originating and terminating gateways to stay in a low complexity non-voice compression codec (e.g., ITU G.711) after prenegotiating a high complexity, voice compression codec (e.g., G.729 or G.726) during a short beginning period of a voice call. The low complexity codec avoids distorted answer back tone leakage associated with previous solutions that use a notch filter to block the leakage, thereby significantly improving the success rate of a VBD call by completely eliminating modem answer back tone distortion caused by high complexity codecs that use voice compression and by completely eliminating use of the notch filter.
A method of improving Voice Band Data (VBD) connectivity in a communications network, comprising:
An apparatus for improving Voice Band Data (VBD) connectivity in a communications network, comprising:
A computer program product having a computer readable medium including computer program instructions recorded thereon that, when executed on a computer processor, cause the processor to:
An apparatus for improving Voice Band Data (VBD) connectivity in a communications network, comprising:
A system for improving Voice Band Data (VBD) connectivity in a communications network, comprising:
Dependencies are inferred from the claim text.