The MicroVAXII serial console port is:

9 pin D with pinout
1 - grnd
2,3 - snd, rcv (crossed to terminal for partial null modem)
8 to 9 - shorted together
(I think, I don't have a manual handy. If I'm wrong would someone please
 correct me.)

The toggle switch enables/disables halt when break is pressed on the
console keyboard
(up is enabled)

The console terminal needs to be set to 8bit, no parity and whatever
bit rate that is set by the rotary dial switch.

The other three position dial switch is usually set to the top (arrow)
position. (the middle position is "language inquiry" for terminals that
can handle multiple character sets and the lower position is "loopback test".
(Loopback test of what, I don't know:-)

For a Vaxstation II (RC or GPX), all you can do is yank out the display
board(s) for now and use a serial console, or use the screen/keyboard
for initial boot commands and then switch to the serial terminal once
it starts booting. (NetBSD doesn't yet have drivers for the display
boards. Hopefully someone will port the 4.4BSD-Lite drivers in, but..)

Have fun, rick
ps: If you go anonymous ftp to ftp.spc.edu, there are some useful notes
    on Microvax hardware. You might also want to direct questions to
    comp.sys.dec.