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A-61124 March 1999 6-1
6 Scanner-unique Commands
This chapter provides information about the scanner-unique
commands used for communication and data exchange between
the scanner and host system.
Scanner-unique commands, which are used to establish or
change the scanner configuration can be executed by sending a
SCSI Send command (with the Transfer Type set to 80H) from
the host system.
The host may query the scanner to determine the current scanner
configuration by executing a SCSI Read command with the
Transfer ID set to the 2-byte scanner-unique command. The
scanner will return the data field value and the scanner-unique
command as data for the Read command.
Scanner-unique
command format
The scanner-unique command format is used to exchange
commands and data between the scanner and host. The scanner-
unique command format is described below.
Data Field Command Field
Data Field — contains numerical data (in ASCII format) and
ASCII character strings. It is variable in length.
Command Field — contains two bytes of upper-case alphabetic
ASCII characters that represent a unique scanner command. The
second command character received in a command sequence
indicates an End-of-Frame condition has been reached.
The following example shows how to create a scanner-unique
command:
This command transmits the numerical value 345.6 with scanner-
unique command DA.
HEX3334352E364441
CHAR 3 4 5 . 6 D A
NOTES:
• One or more of the scanner-unique commands may be sent
using the SCSI Send command.
• A command requiring a data field is not accepted by the
scanner without the data field.
• Do not add leading zeros to parameters unless instructed to do
so for a particular command.
• Limited auditing of the data fields is performed. Invalid data in a
data field may cause unexpected results.