Apple WS 8150 manual Important These

Upgrades		CD-ROM Upgrade - 7
		4 Verify that the three
	Jumper Connectors	jumper connectors are
		installed as shown.
		Important: These
		jumpers configure the
		SCSI device address of
		the CD-ROM drive. The
		CD-ROM drive will have
		a SCSI device ID of 3.
		Verify that no other SCSI
		device installed in the
		computer already has
		that address. If another
		device does have an ID of
		3, change the ID prior to
		installing the CD-ROM
		drive.