Why not using Ofono and Connman ?
This is surprising to see the use of a proprietary telephony layer when there exists mature and well tested open source solution for this. Have you considered the use of Ofono and Connman ? There are designed exactly for this use case.
There already exists a fully open source ofono-ril project. Please use it !
Jcdr 05:06, 23 March 2012 (PDT)