Operating Instructions
Serial Interface Control
IDM corded & IDM Bluetooth
8017159/142O/2019-05-23
© SICK AG · Germany · All rights reserved · Subject to change without notice
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3.5.3
Handshaking Protocol, ACK/ NAK
PROGRAM
F_DEFAULT
Family Code Selection
P.C.
Parameter Selection
Option Code
Handshaking Protocol
SS None (free running mode)
0
SS RTS/CTS (hardware handshaking)
1
SS ACK/NAK (software handshaking)
2
SS Xon/Xoff (software handshaking)
3
NAK Retry Count
SS 3 times
FIN
SS 000-255 times
(3 digits)
ACK Indication
SS Disable ACK Time-out Indication
0
SS Enable ACK Time-out Indication
1
SS Disable ACK Indication
2
SS Enable ACK Indication
3
•
USB COM doesn’t support RTS/CTS handshaking protocol.
•
When the
RTS/CTS Hardware Handshaking
option is selected, the RTS (request to send) and CTS
(clear to send) signals will be issued before normal data communication. This option is very helpful to
ensure the reliability of data communication.
•
When the
ACK/NAK Software Handshaking
option is selected, the Hand-held scanner waits for an
ACK (acknowledge) or NAK (not acknowledge) from the host computer after each data transmission. If
the NAK is received, the Hand-held scanner will re-send the data until receiving ACK. (This function is
not available for IDM Bluetooth Scanners in PICO or HID Mode.)
NAK Retry Count
After transmitting data, the scanner expects a NAK response from the host up to the preset “Serial Response
Time-out”. If the scanner doesn’t get a response, the scanner will issue an error indication and discard the
data. When a NAK is received, the scanner transmits the same data again and waits for either an ACK or NAK.
The scanner issues an error indication and discards the data under following two conditions:
1.
After preset NAK retry counts is received within the preset serial response time-out.
2.
If the preset time-out is up but the preset NAK retry counts haven’t come to the end.
The default retry counts are three times. If you program “0 times”, the scanner will not resend the data to the
host when the scanner receives a NAK. The scanner will discard the data. If you program “255 times”, the
scanner can receive unlimited NAKs from the host within the pre-set serial response time-out.
This function is not available for batch mode. When you enable this function in on-line mode, the out-of-range
function will be disabled automatically.
