Rs-232 Interface - CONCORD BS501 series User Manual

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 host computer, it will issue the RTS signal
first, wait for the CTS signal from the host computer, and then perform the normal data communication.
If there is no replied CTS signal from the host computer after the timeout duration, the scanner will issue
an error indication. By setting (Host idle: Low RTS) or (Host idle: High RTS), the scanner can be set to
match the Serial Host RTS line.
XON/XOFF-An XOFF character turns the scanner transmission off until the scanner receives an XON
character.
ACK/NAK-After transmitting data, the scanner expects either an ACK (acknowledge) or NAK (not
acknowledge) response from the host. When a NAK is received, the scanner transmits the same data
again and waits for either an ACK or NAK. After three unsuccessful attempts to send data when NAKs
are received, the scanner issues an error indication and discards the data.
Inter-character delay: Refer to Inter-character delay of Keyboard wedge.
Response delay: This delay is used for serial communication of the scanner when it waits for a
handshaking acknowledgment from the host.
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