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speeds, from 10MBps to 80 MBps (for Ultra-2). In addition, SCSI connectors come in three styles:

■    DB-25 female

■    Centronics-50

■    SCSI-2 (a special, high-density, 68-pin connector)

The DB-25 female is commonly found on the back of older Macintosh computers and is used to connect to an external disk drive. These connectors have not been widely used in the PC world. Figure 6.5 shows a sample DB-25 female connector.

FIGURE 6.5 A sample DB-25 female SCSI connector

More commonplace is the Centronics-50 interface, which is considered the standard SCSI connector. Centronics-50 connectors have both male and female connectors and typically are used in SCSI-1 implementations. Figure 6.6 shows a sample male Centronics-50 connector.

FIGURE 6.6 Male Centronics-50 SCSI connector

The SCSI-2 connector was so dubbed because it was introduced on systems at the same time as the introduction of the SCSI-2 interface. Typically, a cable connects to the 68-pin connector on one end and connects to either another 68-pin connector or a standard Centronics-50 connector on the other. Figure 6.7 shows a sample high-density, 68-pin connector.

FIGURE 6.7 A high-density, 68-pin SCSI connector


When you connect computers to a network, you may have to deal with the peripherals attached to those computers. A peripheral is any device that is not an actual part of a computer, but is directly attached to it. Some examples of peripherals are printers, modems, speakers, and backup devices. In a network, peripherals can be attached to servers or workstations (and sometimes also directly to the network cable), and “hosted” for other computers on the network. This means you can buy one peripheral and then share it with other computers on the network. It’s important to note that not every peripheral can be hosted, but many, such as printers and modems, can.

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