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8-15
Programming
Software Handshaking
This parameter controls the data transmission process. It may be used in conjunction with
Hardware Handshaking. However, Hardware Handshaking takes precedence. That is, it
takes place before, and ends after Software Handshaking. All references to beepers
presuppose a beeper is present.
The scanner provides four Software Handshaking options; NONE, ENQ, ACK/NAK, and
ACK/NAK with ENQ. Refer to the Software Handshaking diagram, Figure 8-2.
1.
None
No handshaking is selected and data is transmitted immediately.
2.
ACK/NAK Only
The ACK/NAK option checks the success or failure of a transmission. The scanner
expects one of the following host responses after a data transmission:
<ACK> - Acknowledges a valid and successful transmission.
<NAK> - Indicates a problem with the transmission.
Whenever a <NAK> is received, the scanner retransmits the same data and awaits an
ACK/NAK response. After three unsuccessful attempts to transmit the same data, the
scanner aborts any further communication attempts on that message. The beeper
indicates a transmission error by sounding 4 long beeps.
3.
ENQ Only
With this option, the host must request data before the scanner sends it. This ensures
that data transmission occurs only when the host is ready to receive.
When this option is selected, the scanner waits for an Enquire character (ENQ) from
the host before it transmits data. With ENQ enabled, the scanner must receive an ENQ
from the host within 2 seconds after the last activity or the scanner sounds four long
beeps to indicate a transmission error; the unit is now ready to scan again.
4.
ACK/NAK with ENQ
This combines both handshaking options.
Содержание LS 1220
Страница 2: ...LS 1220 Product Reference Guide ...
Страница 3: ......
Страница 4: ...LS 1220 Product Reference Guide 70 12072 03 Revision A January 2003 ...
Страница 23: ...1 8 LS 1220 Product Reference Guide Figure 1 3 LS 1220 Connector ...
Страница 33: ...2 10 LS 1220 Product Reference Guide ...
Страница 71: ...8 14 LS 1220 Product Reference Guide Figure 8 1 Hardware Handshaking ...
Страница 97: ...9 6 LS 1220 Product Reference Guide Code Lengths cont d 1 2 3 4 5 6 7 8 9 0 CANCEL ...
Страница 105: ...9 14 LS 1220 Product Reference Guide Prefix Suffix Values cont d 1 2 3 4 5 6 7 8 9 0 CANCEL ...
Страница 108: ...9 17 Parameter Menus UPC Security Zone cont d 1 2 3 4 5 6 7 8 9 0 CANCEL ...
Страница 114: ...9 23 Parameter Menus Parity Set the type of parity for RS 232C transmission ODD EVEN MARK SPACE NONE ...
Страница 118: ...9 27 Parameter Menus ASCII Data Format Select either 7 bit or 8 bit ASCII format for RS 232C communications 7 BIT 8 BIT ...
Страница 120: ...9 29 Parameter Menus Intercharacter Delay cont d 1 2 3 4 5 6 7 8 9 0 CANCEL ...
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