Most factories have had in-house networks for decades.  Ordinary CAT-5 cable works quite well in electrically noisy industrial environments, because it&#x27;s a differential signal on twisted pair.  In industry, the big problem is getting all the gear to interoperate.<p>There&#x27;s also what&#x27;s called &quot;machine to machine communcation&quot;, much of which takes place over low-cost wireless pager networks.  Many industrial air conditioners, elevators, and vending machines are regularly sending their short, boring, but important messages to a server. There&#x27;s even M2M over Iridium two-way satellite paging, for oil wells and such.  That works anywhere you can see the sky.