| 摘要 |
A modem that operates selectively in the voice-band frequency band and higher frequency bands is provided. This modem supports multiple line codes, like DMT and CAP. The modem uses a Digital Signal Processor (DSP), so that different existing ADSL line codes, such as Discrete MultiTone (DMT) and Carrierless AM/PM (CAP), can be implemented on the same hardware platform. The modem employs a method for interfacing the modem hardware with a host operating system. The method calls a defined set of host interface functions for command/control, calls a defined set of host interface functions for link correction management, calls a defined set of host interface functions for data sending/receiving, calls a defined set of host interface functions for synchronization between voice-band audio and above voice-band audio, and calls a defined set of host interface functions to use the voice-band as control channel and above voice-band as a data channel.
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