NCR RealPOS, Руководство пользователя

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Chapter 5: Programming 5-49
Interface Control
The Interface Control parameter permits control of the transfer of data between the scanner and
the host terminal. The options are None, enable ACK/NAK, enable XOn/XOff, and enable
both ACK/NAK and XOn/XOff.
If enable ACK/NAK is selected, each message sent to the host terminal must be acknowledged
before sending the next message. Receiving the message properly causes an ACK to be sent,
and if there are any errors, a NAK is sent instead and the scanner sends the message again.
Also, any valid message other than NAK or XOn/XOff, if enabled, serves as an ACK as long
as the message from the scanner is completed before the host terminal starts sending the valid
message to the scanner.
An XOff message turns the scanner transmitter off until the scanner receives an XOn message.
An XOn message can be received at any time. If the scanner is sending a message when it
receives an XOff, since these messages can be received any time, data transmission stops after
sending the current byte. When the scanner receives the next XOn, it sends the remainder of
the message. The scanner does not acknowledge XOff and XOn messages with ACK or NAK
messages.
Select the interface by scanning the appropriate Hex 0 through Hex 5 tag.
Check Digit
The Check Digit parameter permits control of the transmission of UPC–A, UPC–E, EAN–8,
and EAN–13 check digits. Scan the appropriate Hex tag (
Hex 0 to Hex F ) to independently
enable or disable UPC–A, UPC–E, EAN–8, and EAN–13 check digits. The default is Hex 1 —
Enable UPC–A, EAN–8, and EAN–13; Disable UPC–E.
RS-232 Prefix Byte
22774
Prefix Byte
A
ASCII Code
B
0
Disable
1
Enable
0 - 7
Hex Character
(ASCII Code Chart)
0 - F
Hex Character
(ASCII Code Chart)
0
Default
2
Your Program
Prefix Byte
A
RS-232
Prefix Byte
2 2
ASCII Code
B
The RS-232 Prefix Byte programming mode controls the use of prefix bytes. If an RS-232
Prefix Byte is used, it is the leading character in each message sent to the host terminal.
Following it is the message data. Refer to the “Parameter Defaults” section earlier in this
chapter for the factory defined default value of each programming parameter.