Fixed Mobile Substitution
Fixed Mobile Substitution, usually abbreviated to FMS, is the use of a mobile phone instead of a fixed, wired, POTS telephone.
Although strictly, this could simply be as the result of a subscriber making an individual choice, the term is usually used to describe a deliberate tactic of a carrier to promote such a behavior.
One such technique is the use of "homezones". Although very popular with subscribers, and delivering good uptake, these are expensive for carriers, and outside of a few specific countries they are not common.
The use of femtocells promises to be a more attractive approach.
The term FMS is in contrast to Fixed Mobile Convergence, which is usually used to describe the use of two different technologies to deliver a similar user experience. Examples include the use of dual-mode handsets with both cellular and WiFi technologies and hand-off between the two.
