On Mar 3 2005, 0:12, Jay West wrote: The console on all PDP-11s is at the same place, 777560-777566 (add "17" in front for a 22-bit system, though). The first word is the receive control and status register (CSR), the next is the receive buffer register, then the transmit CSR, and lastly the transmit buffer register. So if you have a terminal connected, and with baud rate, parity, and word size to match the M7800 settings, simply DEPositing a value into 777566 should cause the corresponding ASCII character to appear on your terminal. If you type a character on the terminal, it should appear in the lowest 8 bits of 777562. Yes. But trying it will tell you if the problem is in the CPU drivers or the memory buffers, for example. -- Pete Peter Turnbull Network Manager University of York