LAUMAS LCB, User Manual

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
CHECK-SUM CALCULATION
The two ASCII characters (
ckck
) are the representation of a hexadecimal digit in ASCII
characters. The check digit is calculated by executing the operation of XOR (exclusive OR) of 8-bit
ASCII codes of only the string underlined.
The procedure to perform the calculation of check-sum is the following:
-
Consider only the string characters highlighted with underlining
-
Calculate the exclusive OR (XOR) of 8-bit ASCII codes of the characters
Example:
character decimal ASCII code hexadecimal ASCII code binary ASCII code
0
1
t
48
49
116
30
31
74
00110000
00110001
01110100
XOR = 117 75 01110101
-
The result of the XOR operation expressed in hexadecimal notation is made up of 2 hexadecimal
digit (that is, numbers from 0 to 9 and/or letters from A to F). In this case the hexadecimal code
is 0x75.
-
The checksum is made up of the 2 characters that represent the result of the XOR operation in
hexadecimal notation (in our example the character "7" and the character "5").
SERIAL PROTOCOLS ALARMS
     
MODE
ASCII __O-F_ __O-L_ __O-F_ __O-L_ __O-F_ &aa#CR
RIP * __O-F_ __O-L_ __O-F_ __O-L_ __O-F_ __O-F_
HDRIP-N
_ERCEL _ER_OL _ER_AD ###### _ER_OF O__SET
CONTIN
_ERCEL _ER_OL _ER_AD ^^^^^^ _ER_OF O__SET
* For RIP remote displays, if the message exceeds 5 digits the display reads

.