DRAGON™ D151
60
Field Descriptions Table
Field Name
Format
Sub-Field
Meaning
Length
1 Byte
Length
Length of message not including the
check sum bytes.
Maximum value is 0xFF.
Opcode
1 Byte
See the
for
details
Identifies the type of packet data
being sent.
Message
Source
1 Byte
0 = Reader
4 = Host
Identifies where the message is
coming from.
Status
Bit 0
Retransmit
0 = First time packet is sent
1 = Subsequent transmission
attempts
Bit 1
Reserved
Always set to zero
Bit 2
Reserved
Always set to zero
Bit 3
Change Type
(applies to
parameters)
0 = Temporary change
1 = Permanent change
Bits 4 - 7
Unused bits must be set to 0.
Data
Variable
number of
bytes
See individual
sections for
details.
Checksum
2 Bytes
2's complement
sum of
message
contents
excluding
checksum.
Checksum of message formatted as
HIGH BYTE LOW BYTE
Note:
The checksum is a 2-byte checksum and must be sent as HIGH BYTE followed by
LOW BYTE
.
Содержание Dragon D151
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