2-1. The format of message packet is as follows:
Length Byte (Prefix: 0x86, 0x87, or 0x88 ..... )
Receiver ID high byte
Receiver ID low byte
Opcode Byte
Data Byte1
Data Byte2
Data Byte3
.
.
Checksum Byte
2-2. Length Byte
This Length Byte is also a prefix. Bit7 must be 1.
EX:
0x87 ==> this packets has 7 bytes length. ( not included Length byte itself )
2-3. Receiver ID
1). Individual receiver ID
---------------------------------------------------------------------
Decimal
14bit binary value
Hbyte Lbyte
Receiver ID
(Digital Video Recorder)
-------
-------------------
------
------ ----------------------
0
0000000 0000000
00 00
ID = 0
1
0000000 0000001
00 01
ID = 1
2
0000000 0000010
00 02
ID = 2
....
126
0000000 1111110
00 7e
ID = 126
127
0000000 1111111
00 7f
ID = 127
128
0000001 0000000
01 00
ID = 128
129
0000001 0000001
01 01
ID = 129
255
0000001 1111111
01 7f
ID = 255
256
0000010 0000000
02 00
ID = 256
....
511
0000011 1111111
03 7f
ID = 511
....
16382
1111111 1111110
7f 7e
ID = 16382
---------------------------------------------------------------------
2). Broadcast ID
---------------------------------------------------------------------
Decimal
14bit binary value
Hbyte Lbyte Receiver ID (Digital Video Recorder)
-------
-------------------
------
------ ----------------------
16383
1111111 1111111
7f
7f all DVR connect to RS485
---------------------------------------------------------------------
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