Symbol LS3478-ER, Reference Manual

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Symbol LS3478 Product Reference Guide 6-14
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).
If Standard RTS/CTS handshaking is not selected, scan data is transmitted as it becomes available. If Standard RTS/CTS handshaking
is selected, scan data is transmitted according to the following sequence:
• The scanner reads the CTS line for activity. If CTS is asserted, the scanner waits up to the 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 any scanned data is lost.
• When the CTS line is de-asserted, the scanner asserts the RTS line and waits up to the Host Serial Response Time-out for
the host to assert CTS. When the host asserts CTS, data is transmitted. If, after Host Serial Response Time-out (default), the
CTS line is still de-asserted, the scanner sounds a transmit error, and discards the data.
• When data transmission is complete, the scanner de-asserts RTS 10 msec after sending the last character.
• The host should respond by de-asserting CTS. The 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 de-asserted for more than 50 ms between characters, the
transmission is aborted, the scanner sounds a transmission error, and the data is discarded.
If this communications sequence fails, the 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.
The DTR signal is jumpered (set) to the active state.
None
Scan the bar code below if no Hardware Handshaking is desired.
*
None
Standard RTS/CTS
Scan the bar code below to select Standard RTS/CTS Hardware Handshaking.
Standard RTS/CTS