A number of communities have expressed a desire for the Serval Mesh (app for Android) software to allow gating of GSM mobile calls to and from Mesh network phones. This would allow a community to place a single phone in a vantage point where cellular service was available, and to use that single service to meet the mobile communications needs of that community.
Interfacing to the in-call audio-stream on Android devices is, however, very difficult to impossible, depending on the handset. However, it appears that Symbian phones are able to perform this function, as evidenced by the existence of a number of call recording applications, such as: http://best-callrecorder.en.softonic.com/symbian and http://gallery.mobile9.com/f/2558051/.
The purpose of this project is to explore the feasibility of initiating, answering and recording calls on preferably an Android phone, or failing that a Symbian S60 phone, and inserting audio from the mesh into the call.
It expected that implementation of a prototype would proceed, including porting Serval DNA to the Symbian operating system if required.
The approach of using a custom ROM on an Android phone may be explored as part of this, as may the use of connecting a IOIO board into the headset connector on an Android phone, and using that to provide a complete audio loop on any Android device. This would be the more universal solution for Android, with the caveat that it requires a bit of hardware.
It would also be possible on Meego based phones, but there aren't many of those.
A member of the public has offered a GBP500 bounty on implementing this on Android:
Carlos de Souza Moura email@example.com 1:00 AM (12 hours ago)
I would pay £500 if someone could make a contribution to this project. The code generated would be available as open source and serval can use it to connect the mesh to external gsm network for cheap.
This technology was first developed in the first half of 2013 as a student project.