Cheapest of all is solder bridge jumper.
Not as easily reversed, but I suppose you could put holes for jumpers for those who want that option.

Tevian wrote on Yesterday, 07:09:

I could still do a "standard" orientation but routing might get tricky. The ISA block would be fine with a 2-layer PCB, but addi […]
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mbandalauk wrote on 2025-08-03, 23:25:

Tevian wrote on 2025-08-03, 11:48:

Okay... I'm looking into it. It shouldn't be too complicated to make an adaptor card for PC/104+. The only issue, I don't have a […]
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Okay... I'm looking into it. It shouldn't be too complicated to make an adaptor card for PC/104+. The only issue, I don't have any PC/104 cards on hand. The technical drawings in the spec sheet look good, so it "should" work. Although, for testing, I'd probably have to get one. 😅

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There is an issue of orientation. In the standard versions, with the ISA connector along the bottom edge, all the pins are crossed.

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A rotation of 90 degrees clockwise makes the connections a bit more straightforward. This makes the CF card slot point up and should be fine

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The next issue is the baffle. A custom PC CARD baffle might not be worth it, so I'm looking for an off-the-shelf one from AliExpress, but I'm not finding one that has all the ports I'd like. A 3D printed one would technically work, but a metal bracket off-the-shelf would be preferred.

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Another fantastic contribution to the community! You're right—you’ll likely need a PC/104+ board for proper testing. The 90-degree rotated version looks excellent. I believe my PCM-3370 would fit nicely, and conveniently, the CF slot would face upwards. However, there might be limited clearance between the heatsink and the EISA connector—see the PCM-3370 board below for reference.

I'd be happy to send you mine for testing if that helps. I’m sure we could work something out, though I’m based in the UK, and unfortunately, shipping costs and potential import duties do make things a bit tricky.

I could still do a "standard" orientation but routing might get tricky. The ISA block would be fine with a 2-layer PCB, but adding the PCI would probably need a 4-layer PCB minimum...

As far as clearance, I'd probably have to get an Advantech PCM PC/104 SBC. And, if I use the PCM-3370 as a base, I'd need to verify the dimensions and pin pitch on some of those connectors.

From the pic you posted, although it's not an isometric image, it "appears" to clear the bottom edge from the heatsink while just sticking out over the top. Right now, there's about 24mm from the bottom mounting hole to the edge of the connector pins.

The attachment Screenshot 2025-08-03 234100.png is no longer available

Thank you, BTW, for the offer of sending me your SBC! The shipping and responsibility to send it back might not be worth it. While the shipping of the backplane to you was about $35, I didn't take into account the tax, which pushed that over $50. Don't worry, I'll eat that cost, as I'm still new to shipping internationally. 😅😎

I've purchased a cheap PCM-3353 from eBay that's probably cheaper than the two-way shipping for your SBC. While it has a different set of external connections, it is a PC/104+ card that I could verify works on the adaptor card.

This is getting extremely interesting! The adapter will likely consist of just connectors, yet it might require a 4-layer PCB. The PCM-3353 board looks excellent—very interesting that it uses an AMD chipset and offers four USB ports, compared to only two on the PCM-3370. In your design, the CF port would be facing upwards, which seems like the ideal orientation. Just make sure the PCM-3353 has both the ISA and PCI connectors physically populated. Some SBCs don’t include both on the PCB by default—specifically, you’ll need the long header pins on the underside.

I've been thinking about the baffle—it’s going to be tricky to accommodate all the ports you might want there. Considering that people (myself included) may need to make their own custom cables from the SBC to the adapter, it’s probably best to prioritise the most essential connectors. I’d say a VGA and a PS/2 port would be the most universally useful, similar to that AliExpress ISA adapter I shared in a previous post. All other ports can be routed to an external bracket, although finding suitable off-the-shelf options can still be challenging.

Sorry to hear you had to pay extra on taxes—I really appreciate it, and I’ll make sure to compensate you next time. Thanks again!

mbandalauk wrote on Yesterday, 17:14:

This is getting extremely interesting! The adapter will likely consist of just connectors, yet it might require a 4-layer PCB. T […]
Show full quote

Tevian wrote on Yesterday, 07:09:

I could still do a "standard" orientation but routing might get tricky. The ISA block would be fine with a 2-layer PCB, but addi […]
Show full quote

mbandalauk wrote on 2025-08-03, 23:25:

Another fantastic contribution to the community! You're right—you’ll likely need a PC/104+ board for proper testing. The 90-degree rotated version looks excellent. I believe my PCM-3370 would fit nicely, and conveniently, the CF slot would face upwards. However, there might be limited clearance between the heatsink and the EISA connector—see the PCM-3370 board below for reference.

I'd be happy to send you mine for testing if that helps. I’m sure we could work something out, though I’m based in the UK, and unfortunately, shipping costs and potential import duties do make things a bit tricky.

I could still do a "standard" orientation but routing might get tricky. The ISA block would be fine with a 2-layer PCB, but adding the PCI would probably need a 4-layer PCB minimum...

As far as clearance, I'd probably have to get an Advantech PCM PC/104 SBC. And, if I use the PCM-3370 as a base, I'd need to verify the dimensions and pin pitch on some of those connectors.

From the pic you posted, although it's not an isometric image, it "appears" to clear the bottom edge from the heatsink while just sticking out over the top. Right now, there's about 24mm from the bottom mounting hole to the edge of the connector pins.

The attachment Screenshot 2025-08-03 234100.png is no longer available

Thank you, BTW, for the offer of sending me your SBC! The shipping and responsibility to send it back might not be worth it. While the shipping of the backplane to you was about $35, I didn't take into account the tax, which pushed that over $50. Don't worry, I'll eat that cost, as I'm still new to shipping internationally. 😅😎

I've purchased a cheap PCM-3353 from eBay that's probably cheaper than the two-way shipping for your SBC. While it has a different set of external connections, it is a PC/104+ card that I could verify works on the adaptor card.

This is getting extremely interesting! The adapter will likely consist of just connectors, yet it might require a 4-layer PCB. The PCM-3353 board looks excellent—very interesting that it uses an AMD chipset and offers four USB ports, compared to only two on the PCM-3370. In your design, the CF port would be facing upwards, which seems like the ideal orientation. Just make sure the PCM-3353 has both the ISA and PCI connectors physically populated. Some SBCs don’t include both on the PCB by default—specifically, you’ll need the long header pins on the underside.

I've been thinking about the baffle—it’s going to be tricky to accommodate all the ports you might want there. Considering that people (myself included) may need to make their own custom cables from the SBC to the adapter, it’s probably best to prioritise the most essential connectors. I’d say a VGA and a PS/2 port would be the most universally useful, similar to that AliExpress ISA adapter I shared in a previous post. All other ports can be routed to an external bracket, although finding suitable off-the-shelf options can still be challenging.

Sorry to hear you had to pay extra on taxes—I really appreciate it, and I’ll make sure to compensate you next time. Thanks again!

No biggy about the shipping cost. I need to learn about it so I know for future shipments. 😅

I did a preliminary route of the ISA block and I'm still leaning towards 4 layer. The stack up will probably be; signal/power-ground-signal/power-signal/power. Like I said, 2 layer would work for ISA only, but the added roughly 100 traces for the PCI would get very tight. Having an inner ground layer means I can route easier on 3 layers.

Baffle aside, the key ports will be needed. VGA, keyboard mouse, USB, and Ethernet. There should be room for those on the standard 100mm baffle. I can see now why the Allen Bradley cards have the 110mm non-standard height for extra ports. Anything else could easily be used on a side bracket. Pinouts for the ports might be tricky as I don't know if there's an industry standard for something a 2 row 2.54mm VGA header... the PCM 3353 I bought doesn't have the same ones on the 3370. I have the stuff to make custom cables, so I guess I'll just use a standard 2.54mm pin header with pinouts according to the 3370 datasheet.

I'll do more research on this when I get a minute.

I bought another 3353 from ebay that has a bag of all the header cables. It's claims to be not working, but for $35, I will have two PC104+ cards for testing. 😄

I can share hundreds of Asus boards in kicad format.
Almost any footprint you desire can be found.
Vga is a pretty standard footprint.

Re: RDRAM vs SDRAM suprisingly not much faster

myne wrote on Today, 03:04:

I can share hundreds of Asus boards in kicad format. Almost any footprint you desire can be found. Vga is a pretty standard foo […]
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I can share hundreds of Asus boards in kicad format.
Almost any footprint you desire can be found.
Vga is a pretty standard footprint.

Re: RDRAM vs SDRAM suprisingly not much faster

When I saw industry standard, I'm saying, "Is there an industry standard pin header for VGA pigtails?" The different manufacturers of these PC104 boards probably run the gamut as far as pinout, pin pitch, ribbon or flex cable, etc... If Advantech for instance had a standard "PCB connector" for there VGA, I could use that as a base. However, even the ones I just bought (PCM-3353) have a different PCB connector for VGA vs (PCM-3370). Meaning I'd need a custom cable regardless of how I implement this on this adapter card. Stuff like serial, keyboard mouse, and USB seem much more "standard". I'm going to do my best to avoid custom cabling, but it might be difficult with the absences of an "industry standard" PCM VGA cable to PCB header for VGA brake out...😉

Oh, the pin header?
I thought it was pretty standard - albeit there might be different pitch pinouts.