Rockwell Automation 2755 2D Hand-Held Scanner - Manual (Page 67)

5–6 Communication Setup (Synapse Cable)
Publication 2755-6.4
Setting RS-232 Synapse Cable Options (Continued)
Software Handshaking
Software handshaking controls the transmission of data. Use
software handshaking instead of (but not with) hardware
handshaking. The four options are:
•
None (default)
•
ACK/NAK Only
•
ENQ Only
•
ACK/NAK with ENQ
•
XON/XOFF
ACK/NAK Only checks the result of a transmission. The scanner
waits for one of two response from the host: ACK which means a
successful transmission or NAK which means there was a problem.
Whenever the scanner receives a NAK, it retransmits the data up to
three times. If an ACK is still not received after three attempts, the
transmission is aborted and the scanner will provide four short beeps.
ENQ Only requires that the scanner receive an enquire character
(ENQ) from the host before sending data. With ENQ enabled, the
scanner must receive an ENQ from the host within a two second
period after the last scan or a transmission error occurs. The scanner
will provide four short beeps to indicate the error.
ACK/NAK with ENQ combines both ACK/NAK and ENQ options.
With XON/ XOFF enabled, the Synapse cable assumes an XON for
the first transmission. The scanner will transmit data until an XOFF
is received from the host device. If an XON is not received within
30 seconds after an XOFF, a transmission error occurs.