Strange Linux problem with mobile broadband and phone calls

[Abraxas]

Hi,

When I'm using mobile broadband on Linux and somebody tries to call me, phone rings for like a second or two and then disconnects automatically.I'm dualbooting with Win7 and this only happens when using Linux and past year or so I have used several Linux distributions and the same problem has occured in all of them . This annoying problem keeps me from using Linux as much as I would like to use. I don't know if this information is relevant but I have same service provider for my broadband on computer, broadband on smart phone (Samsung GS2) and telecommunication services. My mobile broadband modem is Huawei E367. When I try to look up if other people have experienced same kind of problem I find none so this seems rather strange problem... Do you have any insight what's going on and how could I possibly fix it?

[viking777]

Is this your household phone you are talking about that cuts off when using mobile broadband or are you talking about a telephony application on your computer like Skype for example?

When you are using Win7 are you still using the same Huawei modem or does that connect differently?

[Abraxas]

Thanks for your reply.

Is this your household phone you are talking about that cuts off when using mobile broadband or are you talking about a telephony application on your computer like Skype for example?

Sorry, I was a bit unclear in my original post. It is my ordinary mobile phone calls that get cut off after few seconds of ringing. It is clearly related to using Linux, perhaps to Android also. All my internet (mobile broadband connections in PC and phone) and telecommunication services (calls, SMS) are under one contract so it could be a multi-SIM issue or something...

When you are using Win7 are you still using the same Huawei modem or does that connect differently?

I am using the same Huawei modem but it connects differently in a sense that the connection is done via ISP's own separate connection manager program in Win7.

[Exedukator]

I have a similar problem, but with the normal (i.e. non-mobile) phone. I currently use Firefox 14.0.1 on Linux Mint Maya (I was a Ubuntu fan until the wretched Unity came along with 12.04), but I have the same problem if I revert to earlier Ubuntus, and with Kubuntu and Fedora.
My bandwidth is limited to about130 KB/sec since we live in the French countryside at the extreme end of an old telephone line a little over 3 miles long. Recently when I make a download which is at or near the limit of the bandwidth, the telephone is cut off. If a call is in progress, it stops; if I try to make a call, I get only the engaged tone. As soon as the download ends, the phone returns to normal. If I download at lesser bandwidth – e.g. stream music from a radio station at some 50 KB/sec - there is no problem with the telephone at all. Changing from WiFi to ethernet connection makes no difference.
However, the really bizarre bit is that if I make the same 130 KB/s download from the same (dual boot) computer using Window$ XP (shudder!), there is absolutely no interruption to the telephone. Also Win 7 on my wife's portable causes no problem with the phone.
My ISP claims that the interruption is caused by the length of my phone line and that it is not their fault. But if this is the case, I don't see (and they refuse to explain) why Window$ does not produce the same problem. And surely the filter (which, incidentally, I have changed in case it was the problem) is there to isolate phone from internet. Their advice, shorn of all the French niceties, is "use Window$". I won't print my reply to that in case it causes offence, but has anyone out there better advice? Is the Linux-based internet connection in some way more aggressive than Window$, so grabbing more bandwidth to itself? If so, can I turn it down a bit??