Symbol DS6707-DP20411ZZR - Symbol Digital Scanner DS6707-DP, Product Reference Manual

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RS-232 Interface 8 - 13
Hardware Handshaking (continued)
Software Handshaking
This parameter offers control of the data transmission process in addition to, or instead of, that offered by hardware
handshaking. There are five options.
If software handshaking and hardware handshaking are both enabled, hardware handshaking takes precedence.
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None : Select this option to transmit data immediately. No response is expected from host.
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ACK/NAK : If you select this option, after transmitting data, the digital imager scanner expects either an ACK
or NAK response from the host. When it receives a NAK, the digital imager scanner transmits the same data
again and waits for either an ACK or NAK. After three unsuccessful attempts to send data after receiving
NAKs, the digital imager scanner issues an error indication and discards the data.
The digital imager scanner waits up to the programmable Host Serial Response Time-out to receive an ACK
or NAK. If the digital imager 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.
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ENQ : If you select this option, the digital imager scanner waits for an ENQ character from the host before
transmitting data. If it does not receive an ENQ within the Host Serial Response Time-out, the digital imager
scanner 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.
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ACK/NAK with ENQ : This combines the two previous options. For re-transmissions of data, due to a NAK
from the host, an additional ENQ is not required.
RTS/CTS Option 2
RTS/CTS Option 3