A battery cover structure includes a removable cover and a main body. Processing an electronic check is initiated when a user supplies, via a client connected to the Internet or other public network, authorization information that authorizes one or more check payments. A support immediately adjacent the housing carries a rigid grinding wheel having an abrasive outer surface. The client device is adapted to send the input data to a remote location with an indication of a grammar to use for recognition. A decoder receives a measurement result of the first counter, outputs frequency-dividing data for producing a clock for sampling the first character, and also outputs, when the rate of the start bit is more than a preset value, a flag indicating this matter.