Wireless Joint

We are evaluating a Private cellular network in our lab for a project, and for testing we are using a few Sierra EM9190 and Simcom SIM8200EA-M2 modules. We purchased a "USB3 to M.2 Key B 4G 5G Modem Adapter Enclosure with SIM Card Slot – V7" enclosure from The Wireless Haven to test the modules over USB, and both EM9190 (with appropriate jumpers) and SIM8200EA-M2 powers on and connects to the computer. However, both modules cannot detect the sim cards provided by the Private cellular vendor while in this adapter/enclosure.

Both modules when used in different adapters, a M.2 to Mini-PCIe adapter for EM9190 and the Waveshare Raspbery Pi hat for SIN8200EA-M2, can read the same sim cards. Additionally, when we tested with a commercial sim card from T-Mobile, both modules were able to detect and read it while in the V7 enclosure.

I am trying to understand what could be the reason for sim cards from a particular vendor not being detected in this particular adapter. As far as I know the adapter does not have any active circuitry that read the sim card, just pins connecting the sim slot to the module pins. If the module can read a sim card on a different adapter, and can read other sims in this adapter, then it should be able to read that specific sim in this adapter too.

Any ideas or possible explanations would be greatly appreciated.

Are they 6 pin or 8 pin SIM cards?

Have you tested any other SIM cards in the unit, standard carrier cards, to ensure they also do not read?

Didneywhorl wrote: Thu Aug 10, 2023 12:22 pm Are they 6 pin or 8 pin SIM cards?

Have you tested any other SIM cards in the unit, standard carrier cards, to ensure they also do not read?

All sims we have are 6 pin sim cards. And we did test with standard carrier sim cards from T-Mobile and USCellular, and they are detected and read properly.

Hmmm, so a carrier SIM works in the V7 adapter, but your private SIM doesn't? Should be the same SIM design standards I would think.

Can you show a picture of the pin pad bottom of the SIM cards themselves, side by side your private SIM with a standard carrier SIM?

Attached is a photo of two sim cards, left is the vendor's sim, and right is a standard carrier sim from USCellular. Please ignor the wear and tear on the pads, when we started testing it was brand new out of the sim card writer.

Very strange. I'll have to ask around on this one.