Specifications

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Communication Overview
17
COM
Look closely at the PCI card you are considering buying. Does it comply with
all aspects of the PCI specification? Quatech boards do. Can you really afford
the potential aggravation of using a non-compliant board in your system?
Do you see blank spaces on the edge connector
instead of a complete row of gold-plated pins?
Do you see large "pools" or "grids" of ground
signals running all over the board?
Is your board truly Plug and Play or
do you see jumpers for setting basic
configuration parameters such as address?
Do you NOT see a row of tiny capacitors
(usually rectangular) just above the edge
connector on the front or back of the board?
Notice the two tight rows of
"gold fingers" on the Quatech
board. This indicates that all
PCI signals and power pins are
plated, even those that are
unused. The result is better
data integrity because high-
speed PCI signals use the
power pins for return paths.
Notice the loosely spaced
goldfingers and the large
gaps on the non-compliant
board. This indicates that
not all pins are plated, and
that data integrity may be
compromised.
Notice that there are no grids
apparent on the surface of the
Quatech board. This is because all
Quatech boards have a four-layer
board design using separate layers
for power, ground and signals thus
reducing noise and enhancing signal
integrity.
Notice the grids of ground signals
on the front and back of the non-
compliant board. This indicates
the lack of a separate ground layer
and complicates signal routing.
This makes the board more
susceptible to noise and can
compromise signal integrity.
Capacitors which connect
the power signal to a
ground are part of the PCI
specification and are
designed to filter out noise.
As it is fully PCI compliant,
the Quatech board includes
these capacitors. The
capacitors also promote
signal integrity, as high-
speed PCI signals use the
power pins for return paths.
Notice that the non compliant
board is missing the required
capacitors. This omission
makes the board particularly
vulnerable to noise problems
and loss of signal integrity in
high-speed operations.
back of board
back of board
front of board
The Quatech board contains a
controller chip in which all PCI
configuration registers are
properly implemented. This
means that the PCI BIOS can use
the information stored on the
chip to automatically configure
the Quatech board, making it
truly Plug and Play.
The non-compliant board has no
controller chip, and basic
configuration settings such as
address and IRQ must be
selected manually via jumpers on
the board. Not only is this board
not Plug and Play, it has the
potential to conflict with other
PCI devices in the system.