Can EG25-G support AT+CMUX over USB with Raspberry Pi?

IoT Modules LTE Standard Module
1

To whom it may concern

I am currently working on a project using Quectel EG25-G connected to a Raspberry Pi via USB.
I would like to confirm whether the AT+CMUX (GSM 07.10 multiplexing) feature can be used in this configuration.

Our Goal
ttyUSB2: Use as an AT command interface, but we need 3 independent AT channels for parallel tasks:
SMS sending (every 1 minute)
Modem status queries (every 5 second)
Connected PLMN check (every 1 minute)

ttyUSB3: Use for dial-up (PPP) data connection.

Questions
1.Is it possible to enable AT+CMUX when EG25-G is connected via USB to Raspberry Pi?
2.If yes, what is the recommended procedure for:
Activating CMUX mode on EG25-G
Configuring Linux (e.g., gsm_muxd or other tools) to create multiple logical channels
3.Are there any limitations or conflicts when using CMUX together with a PPP session on another USB interface?

Current Environment
Hardware: Raspberry Pi 4 Model B
OS: Raspberry Pi OS (Debian-based, 64-bit)
Quectel Module: EG25-G
Firmware Version: EG25GGBR07A08M2G
Connection: USB
Detected Ports:
ls /dev/ttyUSB*
/dev/ttyUSB0
/dev/ttyUSB1
/dev/ttyUSB2
/dev/ttyUSB3

Current Usage
/dev/ttyUSB2 for AT commands
/dev/ttyUSB3 for PPP dial-up

2

Hi,

Thank you for reaching us.

Let me check internally on your inquiry. Thank you

3

Hi,

Thank you for your patience.
Can you provide your module full FW version using AT+QGMR

Thank you and have a nice day!

4

ttyUSB do not support CMUX. Only the Main UART supports.

ttyUSB2: Use as an AT command interface, but we need 3 independent AT channels for parallel tasks:
SMS sending (every 1 minute)
Modem status queries (every 5 second)
Connected PLMN check (every 1 minute)

All traffic can run over the same ttyUSB2 by deploying an epoll-driven multiplexer.
And you can also use the usbnet rather than the PPP. So that you have another ttyUSB3 for AT funcion.