Reg.,: 3G support in HL8548

Dear all,

We have bought HL8548 Module recently and it responses well for the Commands.

And also able to workout the PPP communication with our server.

But we don’t know whether module works in the 3G or 2G Mode.

We have execute the Command AT+KSRAT=4 to enable the 3G at the modem initialization.

How we able to know Module working in 3G or 2G currently. Is there any command to find it out?

Kindly help us to sort it out.

One way to do it to use the command


Dear sir,
Please provide HL8548 USB drivers for windows 8

Hi Muniraj,

We dont have USB drivers as we are working with Microcontroller (UART) based interface.

@ Krima919,

Thanks for the info.

Some commands only works only in 3G SIM Cards, otherwise it shows error for that commands.

Difference also in CREG response when working in 3G and 2G.

Probably the better way to determine if the unit is on 2G or 3G is with the at+cops? command, the last parameter shows the tech being used, 0 - 2G, 2 - 3G and for LTE capable units it is 7.



Hello ,

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.



Thanks Matt for prompt response.

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 ? :question:



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…


HL8 ethernet - AT commands.txt (1.64 KB)

hey did you work on Cmux serial driver does it work.can u able to open two serial port and use ppp connection and sending AT command simultaneously

Yes It is working fine. We able to open two virtual port and one we kept for ppp and one for AT command.

can you give me one sample driver of it…as i worked on with … nd_hilonc/ but it does not work out…am getting error in serialsignal.ui it say we had old QT .ui one…

you can download below gsmMuxd source code and build your binary