Symbol MiniScan MS XX07 Series Integration Manual page 259

RS-232 Interface
ACK/NAK
When this option is selected, after transmitting data, the scanner expects either an ACK or
NAK response from the host. When the scanner receives a NAK, it re-transmits the data
and waits for either an ACK or NAK. After three unsuccessful attempts to send data, the
scanner issues an error indication and discards the data.
The scanner waits up to the programmable Host Serial Response Time-out to receive an
ACK or NAK. If the scanner does not get a response in this time, it issues an error indication
and discards the data. There are no retries when a time-out occurs.
ACK/NAK
ENQ
When this option is selected, the scanner waits for an ENQ character from the host before
transmitting data. If the scanner does not receive an ENQ within the Host Serial Response
Time-out, it issues an error indication and discards the data. The host must transmit an
ENQ character at least every Host Serial Response Time-out to prevent transmission
errors.
ENQ
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