TWAIN defines a standard software protocol and API (Application Programming Interface) for communication between application software and image acquisition devices (including scanner). TWAIN was developed to meet the need of consistency of application software with devices. TWAIN-compliant means following the basic TWAIN requirements.
SCSI is the abbreviation for Small Computer System Interface. The basic objective of the interface is to provide most computers with device independence within a class of devices. Thus, different devices can be connected or added to the host computers without modifications to system hardware and software. Each SCSI device occupies one address on the SCSI bus. The address (0 to7) is used to select the device for a certain communication and is called the SCSI ID. The default SCSI ID is 2 which you can change if the SCSI ID conflicts with your environment.
The I/O address is used for the communication of the scanner driver with interface card. The MiraPhoto TWAIN driver configures and find the I/O address automatically. You can also adjust it manually.