Q: What kinds of cables do I need to connect SCSI peripherals to my NeXTstation or NeXTcube? Where can I get them?\
\
A: The SCSI standard requires that SCSI cables have a characteristic impedance of at least 90 ohms (100 +/- 10 ohms). This is necessary to prevent "ringing," which can cause incorrect command or data information to be passed among devices on the SCSI bus. Ringing will occur especially if a system drives the SCSI bus at the full rate permitted by the SCSI standard. NeXT hardware drivers are fast and need cables with proper impedance.\
\
There are cables available in the marketplace that work satisfactorily with other computer systems, but have too low a characteristic impedance to function reliably on the NeXT system. In particular, cables supplied for the Apple Macintosh computer are frequently unsatisfactory for NeXT systems. Don't use them.\
\
Cables that connect the 68040-based NeXT systems to most kinds of SCSI peripherals may be purchased from NeXT. The part descriptions and order numbers are:\
\
SCSI-2 to SCSI-2 cable: NeXT order number N7006\
SCSI-2 to SCSI-1 cable: NeXT order number N7007\
\
Note that we refer to "SCSI-2 cables" only because the newest NeXT computer systems use SCSI-2 high-density connectors. The internal implementation conforms to the SCSI-1 specification, Rev. 17b.\
\
The older NeXT systems that use the Motorola 68030 processor have a DB25 connector for external SCSI devices. If you have upgraded to an 68040 board, you will need cables with the SCSI-2 connector.\
\
There are a number of vendors, listed below, from whom you can order cables not supplied by NeXT. You should be prepared to verify these
\pard\tx560\tx1120\tx1680\tx2240\tx2800\tx3360\tx3920\tx4480\tx5040\tx5600 You may be able to connect several cables together to create the configuration you need. For example, to make a cable that has DB25 on one end and SCSI-2 on the other, you could get a cable with female Centronics on both ends, and then attach a N7007 cable to one end, and a DB25 to male Centronics cable to the other end. If you do this, make sure that all the sections of cable have the proper characteristic