Yes, you are correct! It is in vice versa terms (meaning activated) stated here under the Basic usage: “MBIM functions are inactive when unmanaged. The cdc_mbim driver only provides a userspace interface to the MBIM control channel, and will not participate in the management of the function. This implies that a userspace MBIM management application always is required to enable a MBIM function.”
Or other way around, meaning to disable active MBIM function if swapping with, referring here as example, incompatible M.2 modem card with QMI protocol. I don’t think I will test this in practice any time soon but again, it is good to know before buying any other additional or replacement M.2 modem card (with either the same or eventually with different protocol from the current one) with USB interface.
Here below is one example/description for Gemalto Cinterion® ELS81 and some of newer Cinterion® 4G/LTE cellular modules that are implementing the USB MBIM interface:
https://developer.gemalto.com/tutorial/make-els81-eus-mbim-function-works-ubuntu-linux-1804
All of this is not new to me.
What I had stated was that use of a Broadmi BM818 of Europe or the US and then switching to Gemalto of the other variety could create big headaches.
Yes this article notes MBIM management. Much of this is voided or superseded on QMI use, if the modem is to work and visa versa.
There is no concern for a person using MBIM to stay with it or to start and remain with QMI. Going from the one to the other may however be problematic, IMHO.
Now I wonder if I could put the speaker and microphone to an acoustical coupler and get 300 bps?