These look great any idea how much they cost ?
I guess it is possible to use these as they have approval to connect.
My needs would be to have an Arduino data logger collect time stamped information then , connect it to a modem shield which at time interval X rings up another arduino unit or pc with modem and sends some data it has collected .It is ideal for places that have a phone but no internet .
I was also investigating the use of warning module arduino that can call another phone without it being rung up and using the ring tone and length of call to issue basic information to another module that listens for ringing and length of ringing .