Patent ID: 6522731
Filing Date: 2003-02-18
Classification: H04L,H04M

Abstract:
A data communication apparatus which can conduct data communication using the telephone line for audio band communication, comprising:a detection unit which detects whether the audio band communication is being conducted on said telephone line; and a communication unit which conducts data communication through said telephone line with different characteristics for the active audio band communication and the inactive audio band communication based on the detection output of said detection unit, wherein said communication unit includes; an active audio band communication coefficient table for storing the equalization coefficients in the case where the audio band communication is being conducted on said telephone line; an inactive audio band communication coefficient table for storing the equalization coefficients in the case where the audio band communication is not being conducted on said telephone line; an equalizer for equalizing, based on the detection output of said detection unit, the received signal of the data communication by said active audio band communication coefficients in the case where the audio band communication is being conducted on said telephone line, and the received signal of the data communication by said inactive audio band communication coefficients in the case where the audio band communication is not being conducted on said telephone line; and wherein the data communication is conducted through said telephone line with different noise removal characteristics between the active audio band communication and the inactive audio band communication and gain level is adjusted each time separately for on-hook and off-hook states so that gain level at each time in the time domain does not affect the gain level at other times in the time domain.