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standard single-ended SCSI devices on the same card. Cards with
this feature use two buses—one for LVD and one for standard SCSI
devices.
Note
Recognizing SCSI Interface Cables and Connectors 115
If you do need to use single-ended and differential SCSI devices
on the same cable, adapters are available that will safely handle
the connection. Paralan Corporation (4655 Ruffner St., San
Diego, CA 92111, Tel.: (858) 560-7266; Fax: (858) 560-8929,
www.paralan.com) offers the SD10B and SD16B adapters.
Recognizing SCSI Interface Cables
and Connectors
Because SCSI is actually a family of standards, each with its own
cable and connector, matching cables and connectors to the appropriate
SCSI “family member” is important. Use the following figures
to determine this information.
8-Bit SCSI Centronics 50-Pin Connector
Older, narrow (8-bit) SCSI adapters and external devices use a fullsize
Centronics type connector that normally has wire latches on
each side to secure the cable connector. Figure 4.7 shows what the
low-density, 50-pin SCSI connector looks like.
25 1
50 26
Figure 4.7 Low-density, 50-pin SCSI connector.
SCSI-2 High-Density Connector
The SCSI-2 revision added a high-density, 50-position, D-shell connector
option for the A-cable connectors. This connector now is
called Alternative 1. Figure 4.8 shows the 50-pin high-density SCSI
connector.
25 1
50 26
Figure 4.8 High-density, 50-pin SCSI connector.