Patent ID: 7321615

Claim:
A method of analyzing an AT-command comprising: receiving asynchronous transmission serial data in a transmitting portion based on a baud-rate clock from a DTE; analyzing the data received with a controller; generating the baud-rate clock to be output to the transmitting and receiving portion in accordance with instructions from the controller; measuring a span of a start bit of a first character of an AT command transmitted from the DTE based on instructions from the controller to produce a measurement result; analyzing the measurement result in a rate-analyzing portion; outputting frequency-dividing data; producing a sampling clock in a sampling-clock-generating portion based on the frequency-dividing data and outputting, when the rate of the start bit is more than a preset value, a flag indicating that the rate of the start bit is more than a preset value; selecting, in accordance with whether or not the flag has been set, the frequency-dividing data from either the rate analyzing portion or the controller; receiving data subsequent to the start bit of the first character based on the sampling clock; holding the received data; and reading the received data with the controller.