Specifications

CHAPTER 1
Overview of LaserWriter Pro Hardware
10
Internal SCSI Connector
Internal SCSI Connector 1
The LaserWriter Pro printer provides an internal 40-pin SCSI connector. It is mounted on
the surface of the printer’s printed circuit board, above the rotary switch. This connector
enables you to install an internal 2.5-inch hard-disk drive to store fonts, and other
PostScript Level 2 resources. Figure 1-7 shows the relative position of the connector, and
the connector pins. Table 1-7 lists the signal assignments for the connector.
Figure 1-7 Internal SCSI connector
26 /C/D When active (low) indicates that data is on the SCSI bus; when
high indicates that control signals are on the bus
27 /RST SCSI bus reset
28 /MSG When active (low) indicates the message phase is active
29 /SEL Selects between target and initiator
30 /I/O Controls the direction of data movement; when low data is
output; when high data is input
Table 1-6 Signal descriptions for 30-pin SCSI connector (continued)
Pin number Signal name Description
Front edge of printed circuit board
Pin 2 Pin 1
Pin 40 Pin 39
Even
pins
40 39
21
Internal SCSI
connector
Detail
Internal SCSI connector
Left edge of printed circuit board
Components not to scale
Odd
pins