| 摘要 |
PROBLEM TO BE SOLVED: To provide a large-scale integrated circuit for data communication which utilizes a telephone line, a data communication apparatus, a data communication system, and a data communication method. SOLUTION: A first transmission/reception means is used to deliver and receive a pulse amplitude modulation signal in which the amplitude value of data changes into a plurality of stages to and from a 2-wire type telephone cable. Thus, an information amount to be transmitted within a unit time is larger than an information amount to be transmitted within the unit time of the pulse modulation signal. Only a pulse amplitude modulation signal to be transmitted is taken out from among pulse amplitude modulation signals having propagated through a telephone cable by an echo canceler 110. The equalization accuracy of a pulse amplitude modulation signal propagating through the telephone cable is improved by transmission/reception equalizers 109, 112 and 114. Thus, a data format conforms to the telephone cable. The error of the pulse amplitude modulation signal propagating through the telephone cable is corrected by error correction circuits 104, 105. Thus, the data quality is improved. Accordingly, the two-wire type telephone cable transmits and receives high-speed data instead of using a 4-wire type cable. COPYRIGHT: (C)2006,JPO&NCIPI
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