I am having a bit of trouble sending custom COM Port serial data to some LED message boards. I use VB6 but really this is not programming language specific. I send the data and then am supposed to send a checksum value. The commucations manual just says to add the values sent and that is the checksum. But when I use a comport capture program and look at succesful messages I have sent I cannot figure out how they got the checksum. Here are some examples:
You can ignore the first 10 values. The checksum is calculated starting at 02. Then you are supposed to add everything up until the 03 on the bottom row. The 30 30 44 37 is the checksum value. When I add the values between 02 and 03 (including 02 and 03) I get 928h - not 30 30 44 37.
The above example just sends the letter "T" to the board. (Third character on bottom row). The junk before and after the "T" is just formatting info.
So next I sent a "U" to the board and captured the output.
How to remove superseded packages in windows w60 or w61 installation media (.wim) or online system to prevent unnecessary space.
w60 means Windows Vista or Windows Server 2008.
w61 means Windows 7 or Windows Server 2008 R2.
There are various …