Here is my current setup for communications;

A VOIP phone (standard POTS phone) works over a Vigor 2100 Wireless VOIP cable router to a Cisco 2100 cable modem (cheapest 10Mb/s connection service). If the cable service goes down I could replace the Cisco 2100 with an ancient USR8000 + D-link DFM-56OE 56k modem for dial up connection (assuming that POTS service is still avialable). I will have to experiment to see if I can get a shared wireless 56K connection (typically 40Kb/s) and a working VOIP phone connection over dial up connection.
Going back to the year 2000/2001 this was my portable 2G email/SMS/WAP setup. Most of the paging network in the UK was shut down around 2004/6 in the UK.

What is interesting is that Palm at the time also produced a dial up modem attachment, which allowed dial connection over POTS, which is something even the iPhone 4S doesn't have available today.
http://www.amazon.com/Palm-10401U-PalmOn...0669&sr=1-1 So if all the networks go down (POTS, GSM, 3G etc) then I will have to just rely on getting information via Short Wave, DAB FM, DVB-T and DVB-S.