Honeywell 2020 User Manual page 21

When data is scanned, the data is sent to the host system via the base unit. The
cordless image scanner recognizes data acknowledgement (ACK) from the base
unit. If it cannot be determined that the data has been properly sent to the base,
the image scanner issues an error indication. You must then check to see if the
scanned data was received by the host system.
2020 User's Guide
3) Base sends
data to host
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