Pioneer 504CMX Command Reference - Page 17

RS-232C Adjustment Mode Check Sum This is data to which 2-Byte ASCII code is added to a data group returned by a GET command. PC side STX 02 (hex) ID 2 Byte GET command 3 Byte ETX 03 (hex) Set side STX 02 (hex) GET command 3 Byte Data *Byte Check Sum 2 Byte ETX 03 (hex) A detailed example will be given below. Example: The Check Sum value that is added when the GET command GAA returned the following 6-Byte data. Data group (ASCII) + check sum GET command GAA Data (6 Byte) 100128 Check Sum xx (before calculation) The data group is put in to binary code one 47 character at a time and displayed (only the last two digits are displayed) 41 41 31 30 30 31 32 38 When these values are added the result is 1F8 (hex) As the data format, F5 is converted to ASCII code and sent. The following data is output from the plasma display side. STX GET command Data 02 (hex) GAA 100 (missing data) 28 Check Sum F5 ETX 03 (hex) Note: The returned data group will be in capital letters. Please keep this in mind when introducing it into the binary display. Example of Check Sum applications Example 1: when the data is missing one Byte STX 02 (hex) GET command GAA Data (6 Byte) 100 (missing data) 28 Check Sum F5 47 41 41 31 30 30 32 38 The data group is calculated according to the rules by a PC application and when these values are added the result is 1C4 (hex). Here, the check sum [F5 (hex)] and the calculated [C4 (hex)] do not match. Since they do not match, the PC application sends the GET command again and gets the data again. ETX 03 (hex) Example 2: when one Byte of data is unreadable STX 02 (hex) GET command GAA Data (6 Byte) 100328 Check Sum F5 47 41 41 31 30 33 30 32 38 The data group is calculated according to the rules by a PC application and when these values are added the result is 1F7 (hex). Here, the check sum [F5 (hex)] and the calculated [F7 (hex)] do not match. Since they do not match, the PC application sends the GET command again and gets the data again. ETX 03 (hex) 15