6-13
Simple Serial Interface
CMD_NAK
Description: Negative acknowledgment of received packet
Packet Format
Field Descriptions
Length
Opcode
Message Source
Status
Cause
Checksum
0x05
0xD1
Field Name
Format
Size
Description
Length
Length of message (not
including checksum).
1 Byte
Length Field
Opcode
0xD1
1 Byte
Identifies this Opcode type.
Message
Source
0 = Decoder
4 = Host
1 Byte
Identifies where the message is coming
from.
Status
Bit 0: Retransmit
Bit 1-7: unused
1 Byte
Identifies the transmission status.
Unused bits must be set to 0.
Cause
Reason code
1 Byte
Identifies the reason the NAK occurred:
0 = Reserved
1 = (RESEND) Checksum failure
2 = (BAD_CONTEXT) Unexpected or
Unknown message
3 = Reserved
4 = Reserved
5 = Reserved
6 = (DENIED) Host Directive Denied
7 = Reserved
8 = Reserved
9 = Reserved
Checksum
2's complement sum of
message contents
excluding checksum.
2 Bytes
Checksum of message.
Содержание SE 923
Страница 1: ...SE 923 Scan Engine Integration Guide...
Страница 2: ...2 70 37052 01 Rev A February 1999 Symbol Technologies Inc One Symbol Plaza Holtsville N Y 11742 1300...
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Страница 22: ...1 6 SE 923 Scan Engine Integration Guide...
Страница 29: ...2 7 Installation Figure 2 3 Exit Window Positioning CASE 1 CASE 2...
Страница 52: ...4 8 SE 923 Scan Engine Integration Guide...
Страница 135: ...5 83 Parameter Menus Prefix Suffix Values DATA FORMAT CANCEL...
Страница 138: ...5 86 SE 923 Scan Engine Integration Guide Scan Data Transmission Format PREFIX DATA SUFFIX 1 SUFFIX 2 0x07...
Страница 155: ...5 103 Parameter Menus Numeric Bar Codes cont d 4 5 6 7...
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Страница 232: ...Glossary 8 SE 923 Scan Engine Integration Guide...
Страница 236: ...Index 4 SE 923 Scan Engine Integration Guide...
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