| 摘要 |
PURPOSE:To attain the shift control in following to the state of a transmission line by controlling the shift of a transmission speed based on the data transmission speed and an external condition such as terminal state and state of retransmission request from an opposite station. CONSTITUTION:An MODEM controller 4 controls the transmission speed of an MODEM3 based on a transmission speed data CT1 applied from a signal processing section (DSP)10. a response signal DR representing the reception state (normal reception ACK or abnormal reception NACK) or a data transmitted from an opposite station is applied to a buffer 2a and a shift condition check section 2c via the MODEM3, and the section 2c discriminates whether or not the condition reaches a shift-down and shift-up condition. A reception section RX discriminates whether the reception is abnormal reception or not by means of a serial/parallel converter frame error check section 6a of the automatic retransmission control section 6. |
