LAUMAS LCB - Serial Protocols Alarms

- 69 -
 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 .