2-11
Programming
RS-232C Options (Continued)
Hardware Handshaking
If RTS/CTS handshaking is selected, scan data is transmitted with the
following sequence: (Note that the DTR signal is hard wired active.)
•The scanner reads the CTS line for activity. If CTS is asserted, the scanner
will wait up to two seconds for the host to negate the CTS line. If, after
one second the CTS line is still asserted, the scanner will sound a transmit
error and any scanned data will be lost.
•When the CTS line is negated, the scanner asserts the RTS line and waits
for two seconds for the host to assert CTS. When the host asserts CTS,
data is transmitted.
•When data transmission is complete, the scanner will negate RTS after
sending the last character.
•The host should respond by negating CTS. The scanner will check for a
negated CTS upon the next transmission of data.
During the transmission of data, the CTS line should be asserted.
•If the above communications sequence should fail, the scanner will issue
a transmit error. In this case, the data is lost and must be rescanned.