It'll send whatever byte is in register A. Andres > I'm presently designing a Z80 micro-computer system. But there are a > few things I don't really understand yet. ;) Mainly the ports. Like, > if I do 'out (7),a', where does that go, and how does it get there??? > Is it somehow attatched to the address bus? And then it reads the byte > on the data bus? How??? Help me! :)