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ADVANCED PROGRAMMING GUIDE

5. Handshaking Protocol

The RS-232C type scanner supports four handshaking protocols. With these

options of communication protocol, users can tailor the scanner to meet the

requirement of most systems. These handshaking protocols are:

*None: The scanner will transmit any read data unconditionally. The scanner will

not check the receiving device or the transmitted message.

*RTS/CTS: Under this handshaking protocol, the scanner use the RTS pin to

instruct the connected device to transmit data and test the CTS pin for readiness

of the connected device to receive data.

*ACK/NAK: While selecting this option, the scanner waits for an ACK or NAK

signal from the host computer after each data transmission. Normally, the

scanner will temporarily stored the scanned data in the memory buffer before

receiving the ACK or NAK signal. If the ACK signal is received, it will clear the

transmitted data and continue to send the next data. In case of the NAK signal is

received, it will repeat to transmit the same data until receiving the ACK signal.

*Xon/Xoff: During the data communication, if a scanner receives an Xoff (ASCII

013H), it will stop the transmission at once. The scanner waits for a Xon (ASCII

01H) to start the transmission again.

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POSline SM2430 Spezifikationen Seite 72