Redirect A GSM Call Through Wifi To A SIP Phone

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Asterisk Users 4 Comments

Hi all,

I’ve try to search Google about this without any chance. I want to know if it’s possible to use a mobile phone application for redirect automatically incoming calls of a GSM phone connected to Wifi network to a Sip phone. I’ve try to use different mobile phones SIP clients without any success. No one of them can redirect calls automatically. I’ve got Android and BlackBerry phones. Thanks. Sil

4 thoughts on - Redirect A GSM Call Through Wifi To A SIP Phone

  • What you want is not just a SIP client; it also has to integrate with the phone’s own GSM stack.

    You probably will have the most success with Android, because you are going to need well-documented Source Code to stand a chance of getting anywhere. You will need an Open Source SIP client and the Source Code for the stock Android GSM telephony app. You then will have to bodge the two together somehow …..

    Actually, as long as the data packets coming from Android GSM phone are already compressed using the GSM codec, you shouldn’t have to do anything to them to re-send them out over SIP; and similarly for packets arriving by the SIP connection to re-send over GSM.

    This really is not going to be a trivial project. Good luck with it — you’re going to need it 🙂

  • Hi,

    please correct me if I’m wrong, but if the above was possible, then also, current SIP softphone apps would be able to do

    – conference calls with a mixture of GSM and SIP endpoints
    – transfer calls from/to GSM to/from SIP

    which as far as I know, none of the apps offer. If I remember correctly, one of the softphone app programmers provided a reason why the above will never work: you can’t access a GSM call from an app due to security reasons.

    I’m not sure what percentage I’m right, but I’d strongly suggest a GSM
    gateway for the function either with ethernet and SIP support, or an FXO
    port. Much easier project.

    regards Adam