NC: I assume this means "not connected"
RST: probably reset. U8glib can control this:
If you connect RST to pin 5, then use this:
U8GLIB_ST7920_128X64 u8g(4, 3, 2, U8G_PIN_NONE, 5 )
See the datasheet for details.
dbX pins are only used for parallel mode
VOUT is part of the external variable resistor.
Recently there was a thread about this here in the forum
Oliver