Adaptec 2930U User Manual

Contents

A-3Understanding SCSITo determine if your SCSI device supports the SCAM protocol,check the SCSI device’s documentation.To enable SCAM support, see Chapter B, Configuring the SCSI Card2930CU with SCSISelect.Terminating the SCSI BusTo ensure reliable communication on the SCSI bus, both ends mustbe terminated. Termination prevents the signal from bouncing offthe end of the cable and interfering with itself.If the SCSI Card 2930CU is connected at one end of the SCSI bus,you must terminate the device at the other end.If the SCSI Card 2930CU is connected in the middle of the SCSI bus,it will not terminate itself and you must terminate the SCSI devicesconnected to both ends of the SCSI bus.The method for terminating a SCSI device varies. Refer to the SCSIdevice’s documentation for instructions on how to enable ordisable termination.Here is some general information about termination: You control termination on internal SCSI devices by manuallysetting a jumper on the device or by changing the position onthe cable. The internal SCSI device at the end of the cable mustbe terminated. Usually, you control termination on external SCSI devices byinstalling or removing a SCSI terminator module, or by setting aswitch on the back of the device. The external SCSI device at theend of the cable must be terminated. By default, termination on the SCSI Card 2930CU is set toAutomatic. Adaptec recommends that you keep this setting. Tomanually set termination on the SCSI Card 2930CU, seeChapter B, Configuring the SCSI Card 2930CU with SCSISelect. Most SCSI devices come from the factory with terminationenabled. Some SCSI devices include a terminator block or pass-through terminator. See your SCSI device’s documentation forinformation on enabling and disabling termination.