I have been working with different GSM module manufacture for our different product. i am new to Sierra and we are working on HL8548 with Linux platform. using Cmux for ppp connection and sending AT command simultaneously.
My question is , can we send AT command on both USB and UART ports simultaneously to avoid running cmux ?
The short answer is yes, however, there are a few things to consider.
The USB supports multiple AT USB end points so why not just use several of these rather than adding in the UART as well?
When sending AT commands over multiple interfaces make sure you are not sending conflicting commands on different ports i.e. starting a data session on one port and then starting a CS call on another one and getting upset that the data connection gets suspended, etc the permutations are endless. My point is that the division of labour and responsibilities between the ports needs to be clearly defined.
Also with regards the IP connection ou might want to look at the ethernet interface that the HL8 can offer to the Linux system (check out at+kusbcomp in the command manual). Might offer you something easier and PPP uses a lot of overhead so is slower, especially if the unit is forced to fall back to 2G.
so we need to use PPPoE instead of PPP…
do we need to install the driver in linux?. In AT command user guide they mentioned that Comneon8 driver V4.28 or newer has to be installed…
is it for windows or linux ?
For Windows you need specific drivers (major pain) but for Linux it uses standard CDC ECM and ACM drivers so really easy. When you plug it into your system you will see a lot more interfaces added to your system compared to the before you plugged it with the ‘ls /dev’ and ‘ifconfig’ commands.
I have attached an example as to how to use the commands. Shutting the connection down is a bit more tricky, haven’t figured that one out yet…