Terminating the A5159B Adapter

The A5159B adapter has four sets of termination pins, labeled TP2, TP3, TP5, and TP6; they are normally open. TP3 and TP6 are near the bulkhead connectors for Channel A and Channel B, respectively. TP2 and TP5 are along the top edge of the adapter, near the internal connectors. The labels for TP2 and TP5 can be hard to see, because they might be obscured underneath the shorting jumpers. TP2 is in the center of the adapter, next to markings that say, "J4" and "Channel A." TP5 is near the edge of the adapter opposite the bulkhead, next to markings that say, "J7" and "Channel B."

The pin sets are associated with the channels as follows:

	TIP: The connectors labeled J4 and J7 are not used. There is a pin set labeled TP1 on the bottom edge of the adapter, near the PCI connector. This pin set is not used. Leave the jumper for this pin set in the factory default setting (open), where the pins are not shorted together.

When the pin sets are in the open state, the A5159B adapter provides automatic termination when a SCSI cable is connected to the connector.

When you use the A5159B adapter in High-Availability (HA) applications (such as MC/ServiceGuard) and it must be in the middle of the bus, you must disable the adapter's termination.

	NOTE: When you use the adapter in HA applications that use two SCSI HBAs (such as MC/ServiceGuard) and it must be in the middle of the bus, you will need to change the adapter's SCSI ID (for example, from 7 to 6). Each device on the bus must have a unique ID. See “Setting SCSI IDs”.

To disable the adapter's termination, move the jumper from its normal position (on only one of the pins in the pair) to its shorted position (jumpering both pins in the pair). See Figure 2-1 “Termination Jumpers” below.

Figure 2-1 Termination Jumpers

Shorting these pins together causes automatic termination to be defeated. Some other SCSI device (for example, a disk, disk array, or other HBA, as required) must now provide the termination for the bus.

	IMPORTANT: You cannot set the auto termination feature independently for the internal and external connectors. However, you can set the auto termination state of each channel independently of the other channel. If you want to change the state of the auto termination feature, then you must change the jumpers on both sets of pins at the same time.

	NOTE: V-Class systems use a pass-through termination cable and will, therefore, have the shunts/jumpers in the disabled position from the factory for any of the adapters they might use (currently, the A5159B only).

If you need an additional terminator for connecting directly to the A5159B HBA, the appropriate terminator is HP part number 5021-1120 (VHDCI HVD terminator). If you need an additional terminator for connecting to a peripheral on the end of the SCSI bus, order the appropriate terminator needed for attaching to the peripheral (see the peripheral's documentation for more information).