Keithdoxy, you may be right! That's interesting because what you suggest says that ON1200 may instantly change the pin to an input when the bit needs to be high (1) and then changes back to an output to go low (0) in sending the bit stream. Therefore emulating an open collector via the input state when a high (1) is needed. That would help me out because in some programs (using N1200 for example) I have been making the pin an input after sending serial data out because of parallel serial lines. The "O" may take care of that at a bit level.