Adaptec 1742A User Manual

Contents

6. The 50-pin SCSI ribbon cable can now be attached to eachSCSI device. Refer to the device’s installation instruc-tions to ensure proper pin 1 orientation. Pin 1 orientationmust be consistent throughout the system. Keep the rib-bon cable neatly dressed away from the ventilation slotsin the computer system. Keep the ribbon cable dressedaway from possible electrical noise sources or noise sensi-tive components, particularly large microprocessors, mem-ory boards, switching power supplies, and analog dataacquisition boards. If the internal configuration requiresthe cable to come near noise sensitive circuits, make surethat the cable crosses the boards at right angles and isnear the noise sensitive circuits for the shortest distancepossible.WARNINGThe AHA-1740A/1742A requires single-ended devices.The AHA-1744 requires differential devices. Failureto match drive types can result in electrical damage tothe host adapter and the peripherals.7. Carefully reinstall the cover of the computer.8. If an external SCSI subsystem is to be installed, it cannow be cabled to the external SCSI connector projectingfrom the shielding bracket on the back of the AHA-1740A/1742A/1744 Host Adapter. The proper shieldedSCSI cable must be used for proper operation. The exter-nal connector on the AHA-1740A/1742A/1744 is a 50-pinhigh density type connector that ensures correct pin 1 ori-entation on the host adapter. The subsystem, cables, andSCSI terminators must be installed in accordance withthe directions provided with the external SCSI subsys-tem. The addresses selected for external SCSI devicesmust not overlap with the addresses of the host adapteror any other SCSI devices attached internally.padaptec AHA-1740A/1742A/17442-6