8 - 12 DS4308/DS4308P Digital Scanner Product Reference Guide
Check Receive Errors
Select whether or not to check the parity, framing, and overrun of received characters. The parity value of
received characters is verified against the parity parameter selected above.
Hardware Handshaking
The data interface consists of an RS-232 port designed to operate either with or without the hardware
handshaking lines, Request to Send (RTS), and Clear to Send (CTS).
Disable Standard RTS/CTS handshaking to transmit scan data as it becomes available. Select Standard
RTS/CTS handshaking to transmit scan data according to the following sequence:
•
The digital scanner reads the CTS line for activity. If CTS is asserted, the scanner waits up to Host Serial
Response Time-out for the host to de-assert the CTS line. If, after Host Serial Response Time-out
(default), the CTS line is still asserted, the scanner sounds a transmit error, and discards any scanned
data.
•
When the CTS line is de-asserted, the digital scanner asserts the RTS line and waits up to Host Serial
Response Time-out for the host to assert CTS. When the host asserts CTS, the scanner transmits data.
If, after Host Serial Response Time-out (default), the CTS line is not asserted, the scanner sounds a
transmit error, and discards the data.
•
When data transmission completes, the digital scanner de-asserts RTS 10 msec after sending the last
character.
•
The host should respond by negating CTS. The digital scanner checks for a de-asserted CTS upon the
next transmission of data.
During the transmission of data, the CTS line should be asserted. If CTS is deasserted for more than 50 ms
between characters, the digital scanner aborts transmission, sounds a transmission error, and discards the
data.
If this communication sequence fails, the digital scanner issues an error indication. In this case, the data is lost
and must be rescanned.
If hardware handshaking and software handshaking are both enabled, hardware handshaking takes
precedence.
* Check For Received Errors
Do Not Check For Received Errors
NOTE The DTR signal is jumpered to the active state.
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