Symbol LS3408 Product Reference Guide - Miles Data Technologies

6 - 14 Symbol LS3408 Product Reference GuideSoftware Handshaking (continued)ACK/NAK with ENQThis combines the two previous options. For re-transmissions of data, due to a NAK from the host, an additionalENQ is not required.XON/XOFFACK/NAK with ENQAn XOFF character turns the scanner transmission off until the scanner receives an XON character. There are twosituations for XON/XOFF:• The scanner receives an XOFF before it has data to send. When the scanner has data to send, it waits up toHost Serial Response Time-out for an XON character before transmission. If it does not receive the XONwithin this time, the scanner issues an error indication and discards the data.• The scanner receives an XOFF during a transmission. Data transmission then stops after sending the currentbyte. When the scanner receives an XON character, it sends the rest of the data message. The scannerwaits up to 30 seconds for the XON.XON/XOFF