Compaq AA-RHGWC-TE - Manual (Page 90)

The DWZZH contains a differential to single-ended signal converter for each
hub port (sometimes referred to as a DWZZA on a chip, or DOC chip). The
single-ended sides are connected together to form an internal single-ended
SCSI bus segment. Each differential SCSI bus port is terminated internal to
the DWZZH with terminators that cannot be disabled or removed.
Power for the DWZZH termination (termpwr) is supplied by the host SCSI
bus adapter or RAID array controller connected to the DWZZH port. If the
member system or RAID array controller is powered down, or the cable is
removed from the KZPBA-CB, RAID array controller, or hub port, the loss of
termpwr
disables the hub port without affecting the remaining hub ports
or SCSI bus segments. This is similar to removing a Y cable when using
external termination.
______________________ Note _______________________
The UltraSCSI BA356 DS-BA35X-DA personality module does not
generate termpwr. Therefore, you cannot connect an UltraSCSI
BA356 directly to a DWZZH hub. The use of the UltraSCSI
BA356 in a TruCluster Server cluster is discussed in Chapter 9.
The other end of the SCSI bus segment is terminated by the KZPBA-CB
onboard termination resistor SIPs, or by a trilink connector/terminator
combination installed on the RAID array controller.
The KZPBA-CB UltraSCSI host adapter:
• Is a high-performance PCI option connecting the PCI-based host system
to the devices on a 16-bit, ultrawide differential SCSI bus.
• Is installed in a PCI slot of the supported member system.
• Is a single-channel, ultrawide differential adapter.
• Operates at the following speeds:
– 5 MB/sec narrow SCSI at slow speed
– 10 MB/sec narrow SCSI at fast speed
– 20 MB/sec wide differential SCSI
– 40 MB/sec wide differential UltraSCSI
______________________ Note _______________________
Even though the KZPBA-CB is an UltraSCSI device, it has an
HD68 connector.
4–8 TruCluster Server System Configuration Using UltraSCSI Hardware