Mindeo FS390, User Manual, Page: 29 / 127

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6-4 RS-232 interface
Flow control:
None - The communication only uses TXD and RXD signals without any hardware or software
handshaking protocol.
RTS/CTS – If the scanner wants to send the barcode data to the host, it will assert the RTS signal
first, and then waits for the CTS signal from the host to perform normal data communication. If CTS
is not asserted in Response delay, the scanner will issue an error indication.
Two-direction flow control - The scanner asserts the RTS signal when it is OK for the host to
transmit. The host asserts CTS when it is OK for the device to transmit.
XON/XOFF – An <XOFF> character (0x13) turns the scanner’s transmission off unit the scanner
receives an <XON> character (0x11).
ACK/NAK – After transmitting data, the scanner expects either an <ACK> character (acknowledge,
0x06) or <NAK> character (0x15) response from the host. When a <NAK> character is received, the
scanner transmits the same data again and waits for either an <ACK> character or <NAK> character.
After three unsuccessful attempts to send data when <NAK> characters are received the scanner
issues an error indication and discards the data.
Inter-character delay: This delay is inserted after each data character transmitted.
Response delay: This delay is used for serial communication of the scanner when it waits for a
handshaking acknowledgment form the host.