How to determine whether a mini PCI-Express supports the USB Interface?

Question

I'm eyeing the amazing Option GTM671W, which is a half-height mPCIe card that supports both WLAN and 3G. However, it was designed for the mPCIe v 1.2 specification. According to this discussion, its 3G capability requires the mPCIe USB interface.

Using HWiNFO64, I determined that my Dell Inspiron 1545's motherboard (DELL 0G848F) supports PCIe v1.1, and I'm not sure if it supports the mPCIe USB interface. This wireless card is on the expensive side and hard to get, so I'm loathe to take the try-it-and-see approach.

Is there any way to determine whether a given mPCIe slot supports the mPCIe USB interface?

I found the electromechanical specification documents for mPCIe versions 1.1 and 1.2. It seems that they incorporated the USB interface in v 1.1, but I'm still not sure, and I'm hoping someone with more experience could clarify.

Unfortunately, I cannot link to the documents directly due to insufficient reputation. I will update this question with the relevant links when my reputation rises. Please search for the following online:

• PCI Express™ Mini Card Electromechanical Specification Revision 1.1RD
• PCI Express® Mini Card Electromechanical Specification Revision 1.2

Thank you for your time!

Answer 1

Most laptop miniPCIe slots do NOT support USB, but it is very difficult to tell the difference.

The mini PCIe form factor only defines the physical dimensions of the card and slot, not the electrical specifications, therefore the slot can (and is) used for both USB, PCIe, and SATA connectivity and not all slots implement all electrical standards.

This is a source of much confusion which was why the NGFF (m.2) standard explicitly addressed this by adding keying tabs to indicate which slots and cards had USB/SATA/PCIe.

In your particular case the chances are 100% that it will not work unless your laptop already has a SIM card slot. Dell boards often have multiple Mini PCIe slots, but you will need one marked "WWAN" to have any chance of it working. As far as I'm aware, some Inspirons had this option but most do not.

Remember that in addition to the USB interface, the board must also have a SIM card slot and a way for the 3G card to communicate with it. This is hard-wired into the MiniPCIe slot, so a laptop must be designed with WWAN (3G) in mind from the outset.