Remember: The LSIU40HVD is also on the SCSI bus; its termination is automatically enabled when it is connected to the end of the bus.

Differential peripheral devices are normally terminated with external terminators, but are sometimes set with jumpers or with a switch on the peripheral. Refer to the peripheral manufacturer’s instructions and to the user’s manual for your computer for information on how to identify the terminator setting of each device and how to change it.

Caution: The auto-enable/disable sensing feature on the LSIU40HVD may enable termination erroneously if it is directly cabled to another SCSI device or host adapter using the same sensing method. The LSIU40HVD senses SCSI devices by detecting the ground signal on conductor 50 of a 68-conductor SCSI cable. If you use an adapter to connect 8-bit devices externally with a 50-conductor SCSI cable, the ground signal is detected on conductor 34.

The LSIU40HVD automatically covers SCSI bus termination for three different bus configurations, depending on your use of the connectors on the LSIU40HVD (see Figure 2.1). The three bus configurations are:

•only for internal SCSI connections

•only for external SCSI connections

•for both internal and external SCSI connections

Termination on the LSIU40HVD for these three different bus configurations is discussed below.

2.2.4.1Internal SCSI Connections

If internal SCSI device connections to the host adapter have been made, you must terminate the last internal device on the SCSI bus. You must disable the termination on all other devices. Termination on the host adapter is automatically enabled in this case.

Figure 2.12 shows an example of how termination is determined for this SCSI bus configuration.

Detailed Installation Procedure

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