Hardware handshaking, Hardware handshaking -12 – Motorola LS3478 User Manual
Page 90
6 - 12 Symbol LS3478 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 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.
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
NOTE
The DTR signal is jumpered (set) to the active state.