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High audio latency with calls through GSM dongle

alon
2018-08-20
2018-09-12
  • alon

    alon - 2018-08-20

    I've successfully got a RasPBX GSM gateway working using a Huawei E1750 dongle—it is very cool, thanks to those who wrote chan_dongle!

    I live in Spain and travel internationally quite a lot. I would like to continue communicating with friends and colleagues using my spanish phone number, making/receiving calls and SMS. The RasPBX GSM gateway together with my Spanish SIM (located on my home network) seems to provide the functionality that I desire. However performance-wise I am experiencing a painful audio latency of approx. 1 second during a simple test in which I called a spanish landline from a softphone extension located on my home network.

    Searching the web, I was not able to find others that experienced such issues.

    Any hints or tips that will help me troubleshoot or resolve this issue would be greatly appreciated.
    Cheers.

     
  • Walter Sonius

    Walter Sonius - 2018-08-24

    Could you please explain your setup a bit more, since its unclear for me if you use the Dongle for roaming data (voip calls) or let raspbx translate voip to GSM audio calls.

     
  • alon

    alon - 2018-08-30

    Walter, the latter.
    My goal is to route a call into and out of the national telephone network with a SIP client, using the dongle as a gateway. In other words, while traveling the world, I'd like to be able to make outgoing calls and receive incoming calls through my GSM subscriber number. I will be using a SIP soft client on my mobile phone to originate and receive these calls. does this make sense?

     
  • Walter Sonius

    Walter Sonius - 2018-09-12

    Probably not a straight answer you're looking for, but I can only recommand you to try a x86 virtualmachine based debian stretch build using the same asterisk/freepbx version matching your current RasPBX gateway build. If this does work without a audio delay you might have a starting point to debug the difference between ARM/X86 (usb driver) behaviour?

    It seems a lot of work but try virtualbox with USB passthrough of the GSM dongle, and follow instructions from my Opus Howto post to get you started:
    https://sourceforge.net/p/raspbx/discussion/tutorials/thread/855b8b02/#88f3

    Offcourse use real debian for x86 instead of raspbian-lite in your case, it will take 1-3 hours but might give a lot more insight.

     

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