Wireless systems with M2M communications via a computer network with a cellular-type back-up network

A communications network is available to implement at least M2M communications between a transmitting unit and a receiving unit. The units can communicate via the Internet as a primary network. They can also communicate via a cellular-type network. At least some of the units include respective subscriber information to provide access and services via the networks. Groups of units can share a common data plan with other related units. Subscriber information can be included in respective SIM cards. At least one of the SIM cards can provide voice or data service via the common data plan.