Hardware Handshaking; None - Symbol LS9203 Product Reference Manual

6 - 18 Symbol LS9203/LS9203i Product Reference Guide

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 2 seconds for the host
to negate the CTS line. If, after 2 seconds (default), the CTS line is still asserted, the scanner sounds a
transmit error, and any scanned data is lost.
•
When the CTS line is negated, the scanner asserts the RTS line and waits up to 2 seconds for the host to
assert CTS. When the host asserts CTS, data is transmitted. If, after 2 seconds (default), the CTS line is not
asserted, the scanner sounds a transmit error, and discards the data.
•
When data transmission is complete, the scanner negates RTS 10 msec after sending the last character.
•
The host should respond by negating CTS. The scanner checks for a negated 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 transmission is aborted, the scanner sounds a transmission error, and the data is
discarded.
If the above 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.
NOTE The DTR signal is jumpered to the active state.

None

Scan the bar code below if no Hardware Handshaking is desired.
*
None