(Jal)Ling; Third-Party Issues - HP 340 Series Service Manual

Cabling
Cable Options. There are three cable options in the SCSI protocol. The standard
IS
an
unshielded ribbon cable with 50 conductors .
• Alternative 1 is similar to the standard cable except that it is shielded .
• Alternative 2 is a shielded round cable with 25 pairs of twisted wire. Pin 1 is twisted with
pin 26, and so forth.
Note that the ribbon cables are intended to connect devices which are mounted in the same
enclosure. The Alternative I cable was chosen for the SCSI card because there is little chance
that it will connect to a device in the same enclosure as the SPU. The shielded ribbon cable is
entirely suitable for connecting devices which are located in one enclosure.
Connecting Cables. The SCSI option comes equipped with a 0.5-metre, Alternative II shielded
(round) cable, for connecting the SPU to one peripheral device. Cables for connecting additional
devices are available in various lengths from Direct Marketing Division (DMK).
Some cables manufactured under the name "Apple@" fit the mechanical specifications, but will
not function properly with the SCSI card.
The alternative 2 cables for use with the SCSI card are identical to those used on differential
SCSI busses.
Third-Party Issues
The SCSI option has a potential problem unlike most products, in that it is expected to be used
in conjunction with non-HP equipment. Here are some of the possible pitfalls to be aware of:
• Drivers: Any peripheral device must have a driver in HP-UX. The one furnished in the
software is intended for use with HP devices, and probably will not work with non-HP
devices. Users of non-HP devices are expected to furnish their own driver. Normally, this
will be written by the OEM or other volume supplier. However, there may be cases in
which the user is not furnished with a suitable driver. Writing of this driver is still the
user:'s responsibility, and not HP's .
• Service: Occasionally, a combination HP and third-party systems will fail to operate
properly. HP's responsibility extends only to the end of the cable. Once the Customer
Engineer has ascertained that the HP hardware and software is functioning correctly, it
is up to the system owner to pursue a solution.
Several potential problems may occur with connecting non-HP peripherals. Users who connect
non-HP peripherals will have to ensure that they have a suitable driver. Further, there is enough
flexibility in the SCSI standard that a particular combination is not guaranteed to work. Also, if
commands other than those in HP Conlmon are utilized, the HP-UX drivers must be modified.
Functional Description
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