Another market that hasn't been on my radar is the burgeoning fixed cellular business. These devices come in phone and "terminal" forms and provide phone, fax and data service for users who can't get or don't want a normal telco wired line.
Telular told me that a large part of their business comes from Latin America, where their fixed cellular phones and terminals are used instead of conventional wired phones. In areas with inadequate or no existing wired phone infrastructure, it's a lot easier to throw up a couple of cell towers and deploy fixed cellular phones than it is to string cable.
Telular SX6P-300G Fixed Cellular Phone
An alternative approach to Telular's dedicated terminals is provided by AdvanceTec's AdvanceCommunicator. Coming in an array of models to match popular phones, the AdvanceCommunicator combines a charging stand, speakerphone and corded handset. All you have to do is to remember to drop your phone into its cradle when you come home. You can't buy direct from AdvanceTec, but their products are resold by cellular carriers at prices around $250.
The AdvanceCommunicator, however, doesn't connect up your normal phones so that they can use a "docked" cell phone to make and receive calls. For that, you'll need a product like PhoneLabs' Dock-N-Talk, which seems like a better deal at about $150 for the unit and $20 for a cable to match your phone.