6-19
RS-232 Interface
ACK/NAK with ENQ
This combines the two previous options.
ACK/NAK with ENQ
XON/XOFF
An XOFF character turns the scanner transmission off until the scanner receives an XON
character. There are two situations for XON/XOFF:
• XOFF is received before the scanner has data to send. When the scanner has data
to send, it waits up to 2 seconds for an XON character before transmission. If the
XON is not received within this time, the scanner issues an error indication and
discards the data.
• XOFF is received during a transmission. Data transmission then stops after
sending the current byte. When the scanner receives an XON character, it sends
the rest of the data message. The scanner waits indefinitely for the XON.
XON/XOFF