Check Receive Errors; Hardware Handshaking - Motorola Symbol LS4208 Product Reference Manual

6 - 10 Symbol LS4208 Product Reference Guide

Check Receive Errors

Select whether or not the parity, framing, and overrun of received characters are checked. The parity value of
received characters is verified against the parity parameter selected above.
*
Check For Received Errors

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 Host Serial Response
Time-out for the host to de-assert the CTS line. If, after Host Serial Response Time-out, 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 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, the CTS line is not 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 negating 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 the above communication 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.
NOTE The DTR signal is jumpered to the active state.
(Enable)
Do Not Check For Received Errors
(Disable)