(11/72)
4.3 Check code
Check code is the Block Check Code (BCC) between the He ader and the End of Message except SOH.
D
n+1
= D
1
XOR D
2
XOR D
3
XOR ,,, D
n
XOR: Exclusive OR
Following is an example of a Check code (BCC) calculation.
Check code (BCC) D
17
= D
1
xor D
2
xor D
3
xor … xor D
14
xor D
15
xor D
16
= 30h xor 41 h x or 30h xo r 4 5h xor 3 0h xor 41 h
xor 02h xo r 3 0h xor 30 h x or 31h xor 30h xor 30h
xor 30 h x or 36h xo r 34h xor 03h
= 77h
Header
Message
Check code
Delimiter
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
SOH D
0
Reserved D
1
Destination D
2
Source D
3
Type D
4
Length(H) D
5
Length(L) D
6
STX D
7
Data D
8
| |
| |
ETX D
n
Check code D
n+1
P P P P P P P P
Header Message
SOH
Reserved
Destination
Address Source
Address Message
type Message length STX OP code
page OP code Set Value ETX
Check
code
(BCC)
Delimiter
01
30 41 30 45 30 41 02 30
30
31
30
30
30
36
34
03 77 0D
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
D
8
D
9
D
10
D
11
D
12
D
13
D
14
D
15
D
16
D
17
D
18