Hand Held Products SCANTEAM 2070, Системное руководство

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3 - 6
Host Port Communications
Host ACK Selection
Some applications require that the host terminal (or server) approve or reject
incoming bar code data and notify the operator of these actions. These
applications require that the host maintain control over the response indicators
emitted from the source scanner. Turning the Host ACK selection on, configures
the cordless system scanners to respond to commands from the host system.
The following criteria must be met for the Host ACK to work correctly:
• The cordless system must be configured for “Host Port RS-232” (Terminal
ID = 050)
• Both the host terminal and the cordless system must have RTS/CTS
handshaking ("Hardware Flow Control Selection" on page 3-4) enabled.
• Host ACK must be enabled (page 3-7).
• System performance degrades when using Host ACK at rates lower than
9600.
• The host terminal software must be capable of interpreting the bar code
data, make decisions based on the data content, and send out appropriate
escape commands to the source scanner.
Escape commands are addressed to the source scanner via “Application Work
Groups.” Once a command is sent, all scanners in a group respond to that
command. Because of this situation,
it is recommended that each scanner is
assigned to its own group .
The commands to which the scanner responds are listed on page 3-8 and
page 3-9. The <ESC> is a
1B hex . A typical command string is y <ESC> x,
where “y” is the application work group number, “<ESC> x” is the escape
command, and the comma is the terminator.
Up to twenty commands may be strung together to create custom response
sequences. An example of a command is listed below.
0<ESC>4<ESC>5<ESC>6,
The above example will make a scanner in application work group zero beep low ,
medium, high.
Once Host ACK is enabled, the system works as follows:
• The scanner reads a code and sends data to the base/host system. No
audible or visual indication is emitted, unless “Decode Beep” is enabled
(page 3-10). The scanner read indicator goes out upon a successful read.
• Scanner is suspended until 1) a valid escape string is received from the
host system (via the base) or 2) the scanner “times out.”
• Once condition 1 or 2 above has been met, the scanner is ready to scan
again, and the process repeats.