I just received a ZTE MF667 mobile Internet modem. It has two slots: one for the SIM card and one for a microSD card. Is the microSD card required? What is it used for? Is it required for the Internet connection or just a feature so that I can store data on it?
Does the microSD card required?
No.
What is it used for? Is it required for the Internet connection or just a feature so I can store data on it?
Yes, exactly!
Just a feature to store data on it, not required for connection.
Every USB - Modem has a small amount of flash memory to store the driver needed for Windows / MacOS installation. That is why the microSD slot is not needed at all and is just a feature.
As the accepted answer: It is not required, it could be used as SD reader (but slow)
Why it is slow and exist in first place? Well, because such USB modem usually implemented with same IC used for cell phone (like Qualcomm which used in iPhone and Android). Some have full Android OS, and SD storage is emulated to the PC system.
That chip has all features of phone but they are not configured, only SD reader which happens to be easy specially with dual slot holder (SIM+SD). It is same price/cost, developer has only to route wires over PCB. So it is a feature that just come in the way.
Deep reference: https://osmocom.org/projects/quectel-modems/wiki
Myself opened Lonsai HSPA USB stick (LS100) which contains Qualcomm MSM7227/RTR6285 (S1 generation).
I also have mobile Internet modem from Huawei, with a micro SD slot also. These slots are generally used to provide the management software of the modem in order to be set up quickly.
You can use the modem without the microSD inserted.
Yes. The purpose of the micro SD slot is data storage. The data transfer rates are too less when compared to a regular USB drive and u will find storing and retrieving data from such devices will be.painfully slow.
