Wasp Bar Code WLS 8400 FZ 用户手册

6-19

When this option is selected, the scanner waits for an ENQ character from the host before 
transmitting data. If an ENQ is not received within the Host Serial Response Time-out, the 
scanner issues an error indication and discards the data. The host must transmit an ENQ 
character at least every Host Serial Response Time-out to prevent transmission errors.

This combines the two previous options. For re-transmissions of data, due to a NAK from 
the host, an additional ENQ is not required.

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 Host Serial Response Time-out 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 up to 30 seconds for the XON.