PCI card backplate dimensions

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Hi all,
My family has an HP Pavilion slimline PC which has a single PCI card
slot.  It came with a crappy softmodem PCI card installed, which I
decided to replace with a Wireless-G PCI card.  The case is very slim,
about 100 mm wide, so that the DVD drive has to be mounted vertically.
The motherboard is a microATX motherboard with dimensions of 6.7"x6.7"
(it looks like this:
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00503102&lc=en&cc=us&x=0&dlc=en&product=1137823&lang=en&y=0#N813 )

When I removed the modem card, I found to my surprise that the
backplate of the modem was actually significantly shorter than a
standard PCI card.  Perhaps a little ASCII art will illustrate what I


                /                 =/
               /                _=/
              /                /_
             /                 =/
            /                _=/
           /                /
          /                /_
|O|           _                \_   ^
| |          |_| O O O          _|  | ~ 20 mm
| |____________________________/    v
|/                         <----->
                           ~ 16 mm
  <--------- ~ 120 mm ----------->


                  /               =/
                 /              _=/
                /              /_
               /               =/
              /              _=/
             /              /
            /              /_
        |O|    _               \_   ^
        | |   |_| O O O         _|  | ~20 mm
        | |____________________/    v
        |/                 <----->
                           ~ 16 mm
          <------- ~80 mm ------->

Basically, this PCI card is totally identical to a "normal" PCI card
that would go in any mini-ATX desktop case, EXCEPT that the backplate
is only 80 mm long from the tab to the point where it screws into the
chassis, rather than the 120 mm or so for a "normal" PCI card.  This is
presumably to allow a slim case (the whole case is only about 100 mm

Since the card itself was only about 60 mm in depth, I was able to make
the "normal" PCI card card fit in this case, after some rather heroic
modifications.  I had to remove the backplate from the card, cut it
short with a hacksaw, bend it, and drill a hole for the mounting screw.
I'm wondering if anyone knows what this shallow-depth PCI card is
called for future reference.

I've had trouble finding publicly available documentation on the
official size of PCI cards.  Wikipedia has only the barest information:
http://en.wikipedia.org/wiki/Peripheral_Component_Interconnect#Card.27s_physical_size .
 I gather that a "standard" PCI card that fits a modern motherboard is
actually a "half-length" PCI card.

Thanks for any advice,

Re: PCI card backplate dimensions

On 21 Dec 2006 14:54:36 -0800, "Dan Lenski"

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Nice ASCII art.  That's probably a "low profile" card
bracket.  Not as common, but still a standard.

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Low profile.  You can (with a little hunting) find some low
profile network adapters, though many of the wireless ones
that short (PCB itself) are inferior quality... it seems
most of the good ones are a little more than 80mm from
bracket tip to card PCB top edge.  I probably would've used
a USB adapter or the built in ethernet port to a bridge
capable access point or capable router (the lines on what
each is and can do are blurring, based on installed

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Well it could be a full length, it'll still fit, but with
today's integrated chipsets (for whatever the PCI card does)
you don't often find cards that need to be that big, not for
the past half a decade or more at least.  Today video cards
may be the largest on average, though most people aren't
using such PCI video cards anymore unless they bought an OEM
system lacking anything better to interface a video card

Re: PCI card backplate dimensions

kony wrote:
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Thanks Kony!  Looks right to me... why didn't I think of that?  I found
the spec on it:

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Good to know, thanks!  It's strange because many PCI cards are shallow
enough to fit this form factor easily.  It's too bad that such cards
don't come with replacement brackets, it's just a 10-cent piece of
sheet metal basically.

I searched for low-profile PCI cards and it seems like some of them are
labeled as such based on the depth of the *card* and NOT the dimensions
of the bracket... for instance this one here:
 It's clear from the relative lengths of the pins and the bracket that
the bracket is about 120 mm... so it's clearly not a low-profile
bracket.  Is this a term that's abused a lot?


Re: PCI card backplate dimensions

On 21 Dec 2006 15:39:32 -0800, "Dan Lenski"

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Yes, but there are SO MANY different product flaws that 10
cents would solve, it's not surprising they're too cheap to
include 2 brackets.

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Unfortunately yes, it seems that somehow marketing
departments saw short cards called low profile and they
didn't "get it", what the point of it was... that it has to
have the bracket or it's pointless unless the buyer wants
to, is willing to do what you did to shorten it.  I've had
to shorten a few brackets before too, and on one I didn't
want to destroy the original bracket yet because I suspected
the card I was trying to use might not "cut it", was a
wireless card in a system pretty far away from an access
point.  I just too a piece of sheet aluminum and cut it to
size, but that was easier because being a NIC, it only
needed a couple small circular holes for the R-SMA jack and
an LED.

Re: PCI card backplate dimensions

Dan Lenski wrote:
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In the low profile video cards on Newegg, only a few cards ship with the
necessary bracket. I guess you have to shop for brackets separately,
in a lot of cases. And getting a bracket with the right hole pattern,
for any needed connectors, is the next issue. It cannot cost a company
very much, to ship a low profile bracket, with a low profile card.

Here is a bracket for a video card.

Someone wants to make a little more profit on this one.

I did find a site, that offered a few different kinds of brackets,
but I cannot find it now. Guess I didn't bookmark it.

The main benefit to a manufacturer, of making a low profile add-in
card, is saving on the size of the PCI card blank. That is why
they make the cards. It isn't generosity, as in making a low
profile, because of a large demand. I think that may be why the
card is low profile, and the bracket is regular profile. They
save on PCB material, and yet have a regular profile bracket
which fits the hottest shopping category. Throwing a low profile
bracket in the kit, would be admitting that people have low
profile computers :-)


Re: PCI card backplate dimensions

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For what it's worth, I just installed a D-Link wireless card G and B
compatible, model WDA-1320 in a friends computer.  The box came with a
standard full sized mounting bracket installed on the card BUT the box also
contained a replacement bracket they called a "Low Profile Mounting Bracket"
in the box just in case I wanted to install the card in a machine like you

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