For standard SCSI connections:

A DB 25-pin to 50-pin Centronics-style cable to connect with your first external device.

One 50-pin to 50-pin Centronics-style cable to connect with each additional external device that you have.

An external "terminator" either standard "passive" or (preferably) "active".

For Fast/Wide SCSI connections:

A Fast/Wide SCSI adapter card, either PCI or NuBus installed in your computer.

One or more Fast/Wide capable external devices, such as an AV-optimized hard drive.

One 68-pin to 68-pin cable for each Fast/Wide external device that you have.

No tools are needed for either type of device.

Allow at least 3 minutes to organize your hardware and cables, 10 minutes to shut down your computer and connect your devices, and 5 minutes to reboot and troubleshoot.

2torial #0431: Learn2 Connect External SCSI Devices (Macintosh OS) SCSI, not $%@*! The term SCSI (pronounced "skuzzy") sounds like a dirty word, but it actually stands for Small Computer System Interface. Essentially, it's how all Macintoshes (except for a few obsolete ones) prior to the iMac and the new blue-and-white G3s "talk" with external devices such as hard drives, CD-ROM drives, and removable media. Some PCs also rely on SCSI. Making things a little more complicated is the development of Fast/Wide SCSI, a newer standard that increases the amount of information streaming through the cable connecting your computer with those external devices. Although it's not exactly as simple as plugging in a toaster, SCSI does make it pretty easy to expand your computing capability in unit-by-unit increments. Note: If you have an iMac, this 2torial does not apply to you. You have what's called USB (universal serial bus) ports. To add a USB peripheral, simply plug it in and load the appropriate drivers. USB devices are hot-swappable, meaning after you plug in your new device, you don't need to reboot your computer before using it. Also worth mentioning is Firewire, an up-and-coming replacement for the waning SCSI interface. Firewire is much like USB in that you simply plug in the new device and go, but it's much faster and more expandable. Drivers are automatically loaded by the device itself. A Firewire chain can hold up to 127 devices and operates at speeds much faster than SCSI and USB. Featured in the blue and white G3s, Firewire devices are just beginning to hit the market. Keep in mind that there are a few rules that govern all modern SCSI "chains" (the collection of SCSI devices attached one to another, and then to your computer): A maximum of seven external devices may be connected to your computer in each SCSI chain. The combined length of all cables used cannot be longer than 18 feet, 6 feet is the recommended total length for older (pre-1992) computers. The chain must be "terminated" at the final device. Some devices have built-in "active" termination, and should be placed at the end of your chain. If none of your devices have this feature, you may use the external "passive" terminator that came with the device or purchase an "active" terminator from a source such as APS Technologies. Each device must have an individual "ID number" assigned to it. No device on the same chain may duplicate another's ID number. Typically, no device can be set to the address 7 (seven), since that is reserved for the computer's CPU (central processing unit). .Step 1