laptop - Mini PCI Express <-> ExpressCard compatibility

Is it possible to plug a mini pci-e card such as the BCM970015 into an ExpressCard connector? Basically I am asking if I could put a mini pci-e card inside am empty ExpressCard card without any extruding components.

Information gleaned from wikipedia suggests they might be compatible.

1. Physical
   • mini pci-e 1/2 size: 30×26.8×[1+components]mm vs expresscard 54: 34/54×75x5mm.
2. Electrical
   • 1.5V or 3.3V
3. Connection
   • 26 pins
   • direct connection to the system bus
   • USB 2.0 or PCI Express ×1 access (subset of connections provided by mini pci-e)

Edit: Clarify question.

Both Mini PCI Express and ExpressCard provide direct access to PCIe ×1 and USB 2.0, but do not provide physical PCIe ×1 or USB 2.0 connectors (I assume). Rather there is a custom connector (mini pci-e connector?), and access to which bus (PCIe or USB) depends on which pins are utilized, I assume.

I am asking two questions:

• Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard slot.
• Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard card.

By compatible, not only do I mean physical form-factor, electrical specification and connection/pin-out but also protocol. You can think if it as, "after plugging them together, will they just work, without any adapters".

For the record I am aware of a device such as PE3B, but am considering creating my own from a half-size mini pci-e card and a empty ExpressCard card. I've run out of mini pci-e slots in my laptop, but have a spare ExpressCard slot.

Edit: After accepting the answer, I've decided to post some useful links and notes in case anyone has similar questions.

Specifications:

• ExpressCard specification
• PCI Express pinout
• ExpressCard/PCI Express ×1/PCI Express Mini pinouts
• ExpressCard pintout
• ExpressCard card physical details

ExpressCard notes:

• When using PCI-e, make sure to pull pin#3(CP USB) low and pin#17(CP PE) high
• To support hot plugging, need a pin#13(PERST, PCIe Reset) 100ms delay circuit
• For power gating (save power), use pin#16(CLKREQ)

Purchasing empty ExpressCard card "kits"

• FCI Product Catalog
• Retailers
• Mouser sells to consumers (I think)

It is possible to bring the PCI-E 1x pins present in an ExpressCard slot to a Mini PCI-E connector, or even a normal PCI-E 1x connector. Gaming enthusiasts have succesfully used full size PCI-E graphics cards to add external GPUs to laptops.

However, all adapters I've seen either use a cable and a separate PCB assembly (ExpressCard to PCI-E), or they protrude a lot outside the ExpressCard slot (ExpressCard to Mini PCI-E).

Edit based on your clarification:

Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard slot.

No, the connectors and pinouts are different. Expresscard has a single row of 26 contacts, while Mini PCI-E cards have 26 contacts on each side with a notch in between.

Is the connector on the mini pci-e card compatible with the connector inside the ExpressCard card.

There is no other connector inside a normal (not adapter) ExpressCard than the one that plugs to the ExpressCard slot. On the card side of the connector, it is soldered to the PCB. Since the pinout is different, it is not possible to directly swap the ExpressCard PCB with the Mini PCI-E card.

However, you should be able to do something similar to this: solder the required cables between an ExpressCard connector and the Mini PCI-E card, or even design a small adapter PCB. It should work, and it would be a very cool hack.