Editing Apple Workgroup Server 9650 (section)

== Three SCSI buses ==
The 9650 has three internal SCSI buses, and getting termination wrong on them can damage the logic board.<ref name="ss" />
* Ultra Wide SCSI-3 (68-pin) on the JackHammer SE PCI card: all internal hard disks, up to four devices, 40 MB/s. ID 0 is the factory hard disk and ID 1 the optional second disk, both terminated; the card is ID 7, also terminated; IDs 2-6 and 8-15 are free. Anything else added to this bus must be unterminated. Apple warns that a terminated device here may severely damage the logic board.
* Fast SCSI-2 (50-pin, 10 MB/s): the CD-ROM drive and the tape drive. These ship unterminated, so a 50-pin terminator block sits on the end of the ribbon cable. Leave it there when adding an unterminated device; remove it and put the new device at the end of the cable if the device is terminated.
* SCSI-1 (50-pin, 5 MB/s) connector on the logic board, which Apple advises against using.

Do not use the external connector on the Ultra SCSI card. Apple does not recommend external devices on it because of Ultra SCSI signal limits.<ref name="ss" /> Devices on different buses may share an ID number.<ref name="ss" />