Hallo Oleg,

I must confess, that I do not have a cell phone. So, my question about meaning of 'cu' was seriously meant! I didn't know it, really.

Yes you are right with your examples, it's difficult to draw the line. But nevertheless there's a difference! You would never write 'u' for 'you' in a serious letter or find in a serious datasheet or textbook, but 'MCU' , 'ALU' etc.

Kai