MC7354/MC73xx Sending AT Commands While in a PPP Connection


I am trying to send AT commands to the MC7354 modem while in a active PPP connection and I seem to be having issues.

OS: Ubuntu 12.04
Kernel: 3.2.0

In /dev, the modem brings up ttyUSB0 through ttyUSB5. I am using /dev/ttyUSB2 for the PPP connection, and is the only port I seem to be able to send AT commands to and get a response. The problem is I can not send AT commands to ttyUSB2 while I am in a active PPP connection because the port gets locked. I am using wvdial to setup the connection and the data connection seems to be working fine.

I know most modems have a port for the PPP data connection and another port to send the AT commands, but I seem to not be able to get any of the other ports doing anything besides the ttyUSB2 port.

I am trying to talk with the other ports with minicom: 115200 baud - 8 bits none parity, 1 stop bit.

Is there a AT command to get the other ports working? Not sure what I am doing wrong.

Thank you for your responses in advance.


Do you have to use PPP?

There are better ways to setup a data connection. If the QMI driver(gobi net and gobi serial) is installed and you use a MC7304 you can send the following at commands:

This will give you a ETH interface(using qcqmi) in Linux and you can use the AT commands port for AT commands.

The other option is to use the QMI SDK so that you can use the QMI interface directly.

Can you do the same thing with the MC7354? I only ask, because that is what I have.

What is the minimum kernel version I need to get the QMI working? I currently do not see anything but ttyUSB0-ttyUSB5 show up.

Is there another way to setup a active data connection on this modem, while still being able to get things like signal strength, mode, band, etc?

I have only used AT commands in the past, so if there is a better way, please let me know.

Thank you

For MC7354 I would recommend to use the Linux QMI SDK. It include examples to setup data connection and many other things. You must contact your FAE to get access to the SDK.

Ok, I have a email out to my rep.

Thank you for your help.