Which Huawei 3G modems allow you to surf the Internet and send SMS at the same time?

Question

Iron

I have one of the simplest modems - Huawei E173.
I never found complete documentation on AT commands for it, and from fragmentary information I got the impression that if I went online through this modem, the port for AT commands is busy, and there are no other ports through which the modem could be controlled (including sending SMS) is not provided.
I heard that the GSM specification provides for a certain CMUX protocol, designed just to solve such problems - multiplexing data streams and commands on one port. Here is an example: www.roundsolutions.com/techdocs/docs_gsm_modules/C...
But it seems that Huawei does not use this CMUX.
Hence the question: which Huawei modems (preferably, but not necessarily those offered with contracts of cellular operators) support in some form the ability to simultaneously surf the Internet and send and receive SMS (do not offer sending SMS through all sorts of gateways - it is of interest "native" interface of AT-commands.If
there are any - how exactly this is done, I ask for links to the documentation.

Answer 1

CMUX None.
And then - what OS. If Linux, then e173 is defined as three ttyUSB devices. 0 - DATA port through which ppp goes, 1 - Debug Interface, and 2 - service port that understands AT commands and gives unsoliscated statistics. You can send sms through it. One BUT - the PPP session will not break, but at the time of sending SMS, it will slow down.

Answer 2

See my comment above - I want to send commands there myself.
I tried the second port from root - it seemed to work, but somehow through a stump deck: I see both modem and NetworkManager command indication messages at the same time, and it sometimes reacts to my commands, sometimes it doesn’t.
You need to find a way to "penetrate" there, and without root.