2 - 18 2020/4820/4820 i User’s GuideHost ACK SelectionSome applications require that the host terminal (or server) approve or rejectincoming barcode data and notify the operator of these actions. Theseapplications require that the host maintain control over the response indicatorsemitted from the source image scanner. Turning the Host ACK selection on,configures the cordless system image scanners to respond to commands fromthe 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 =000) or USB COM Emulation (terminal ID = 130).• RTS/CTS is defaulted off. You must enable it if the host system requires it.• Host ACK must be enabled (page 2-19).• System performance degrades when using Host ACK at rates lower than9600.• The host terminal software must be capable of interpreting the barcode data,make decisions based on the data content, and send out appropriate escapecommands to the source image scanner.Escape commands are addressed to the source image scanner via “ApplicationWork Groups.” Once a command is sent, all image scanners in a group respondto that command. Because of this situation, it is recommended that eachimage scanner is assigned to its own group in host ACK mode.The commands to which the image scanner responds are listed on page 2-20.The is a 1B in hex. A typical command string is y x, where “y” isthe application work group number, “ x” is the escape command, and thecomma is the terminator, which is required.Commands may be strung together to create custom response sequences. Anexample of a command string is listed below.0456,The above example will make an image scanner in application work group zerobeep low, medium, high.Once Host ACK is enabled, the system works as follows:• The image scanner reads a code and sends data to the base/host system. Noaudible or visual indication is emitted until the image scanner receives anescape command. The image scanner read illumination goes out upon asuccessful read.• Image Scanner operation is suspended until 1) a valid escape string isreceived from the host system (via the base) or 2) the image scanner “timesout.”• Once condition 1 or 2 above has been met, the image scanner is ready toscan again, and the process repeats.Time out is indicated by three rapid beeps at the same pitch. A time out occursif the source image scanner does not receive a valid escape command in 10seconds. If a time out occurs, the operator should check the host system tounderstand why a response to the image scanner was not received.
