Patent ID: 7881445

Claim:
A data communication apparatus, being capable of performing data communications in a plurality of communication modes, comprising: a noise information memory for storing noise information to indicate a degree of noise on a current communication line; a mode memory for storing the plurality of communication modes and a degree of noise allowed for each of the plurality of communication modes; and a mode change control unit for reading noise information indicating the degree of the current line noise from the noise information memory, the mode change control unit being configured to compare the degree of current line noise with the degree of noise allowed for a default communication mode during an on-going startup procedure for the default communication mode but before any communication mode is selected for communication, to select, from the mode memory, a communication mode corresponding to the degree of current line noise from the plurality of communication modes, and if the selected communication mode is different from the default communication mode, to stop the on-going startup procedure for the default communication mode and proceed to perform communication using the selected communication mode.