I have no Idea how to add TCP/IP and finally Sockets or HTTP atop GPRS.
So my request for comment what steps to go/learn to do so.
My opinion of how it could work:
TCP/IP-Model has 4 Levels setting atop each other and using communications-interfaces between layers. On trace the Application level is the most inner part of data package and Network-Interface is physical frame signals:
Application -> HTTP/Sockets
Transport -> TCP
Network -> IP
Network-Interface -> GPRS
I think the SMS/Voice ability is part of the higher levels. So I would expect to use the interfaces they use to work with Network-Interface-Layer/GPRS.
Because there are TCP/IP Libraries for C++ it should be the choice to use one of them to get a network connection to your provider. Based on this the node.js net module could do the final work because if I know right all Application-Level-Modules base on it. So lua could use this to connect to GPRS.
So long my opinion how it could work.
My problem: If it is not possible to get a Remote-Support-Connection to the Tessel it isn't a choice for a lot used-cases. Other solutions can do. I would be very sad to went away from the great idea of Tessels mission
Elsewhere it would be nice to have the G3/G4 Module is in planing with no timeline. But my deadline for decision isn't far away.