Patent ID: 7720138

Claim:
A communication system for carrying out communication by setting a transmission speed, comprising: a transmitting device to transmit one frame of measuring data which contains a start bit to be added to a head of the data and a stop bit to be added to an end of the data and which is used for a signal receiver to measure a transmission speed; and a receiving device having a framing error detector to receive the measuring data for detection of a framing error which occurs when a transmission speed of a signal transmitter does not coincide with a transmission speed of said signal receiver and normal detection of a stop bit is impossible and to generate information about detection of a framing error and having a transmission speed measurer to measure a transmission speed of said transmitting device based on information about detection of a framing error, wherein the framing error detector is configured to detect at every detecting point and to count a first number of framing error detection points and a second number of framing non-error detection points, wherein a transmission speed is measured based on a measuring point interval time, the first number and the second number.