SCSI Commands

The commands supported by EPSON scanners are explained below.

If the Link, Flag, and reserved bits of a command are a value other than 0, an error occurs and the command is not executed.

1.Test Unit Ready

If the scanner is ready for operation, Good status is sent; if an error occurs at this time, Check Condition status is sent.

2.Request Sense

The sense data in the scanner is sent when a request is received. Sense data is 8-byte data in the extension sense data format.

The number of sense data bytes sent is determined by specifying the assigned length. If more than 8 bytes are specified, 8 bytes of data are sent and then Data In Phase ends. If a length of 0 is specified, 4 bytes of sense data are sent. See Sense Data for details.

3.Inquiry

Device type data for the scanner is sent. There are 40 bytes of Inquiry data. Refer to SCSI specifications for a description of Inquiry data. The number of bytes of Inquiry data sent at this time is determined by specifying the assigned length. If more than 40 bytes are specified, 40 bytes of data are sent and then Data In Phase ends. If a length of 0 is specified, an error will not occur, but no data will be sent and the command will be terminated.

Interface Specifications A-15