CON device (bits 1,0):
	00 - TTY on 88-SIO at 0/1
	01 - CRT on 88-2SIO at 10h/11h*
	10 - BAT (indirect through RDR and LST)
	11 - UC1 on 88-2SIO at 12h/13h

RDR device (bits 3,2):
	00 - TTY on 88-SIO at 0/1
	01 - PTR on 88-2SIO at 10h/11h*
	10 - UR1 on cassette port (SIO at 6/7)
	11 - UR2 on 88-2SIO at 12h/13h

PUN device (bits 5,4):
	00 - TTY on 88-SIO at 0/1
	01 - PTP on 88-2SIO at 10h/11h*
	10 - UP1 on cassette port (SIO at 6/7)
	11 - UP2 on 88-2SIO at 12h/13h

LST device (bits 7,6):
	00 - TTY on 88-SIO at 0/1
	01 - CRT on 88-2SIO at 10h/11h*
	10 - LPT on 88-LPC at 2/3
	11 - UL1 on 88-2SIO at 12h/13h

* Default IOBYTE