CEBus is a standard for a communication technology intended to allow low data rate communications over 60Hz power wiring. CEBus uses swept ("chirped") 100-400Hz signals that will pass through transformers and other power distribution components but are sufficiently wide in range to allow point frequency noise sources such as light dimmers to be ignored.

CEBus includes a specification for a Common Application Language (EIA-CEMA 600 and 721), and a "Home Plug and Play Specification" that is intended to allow devices from different manufacturers to by plugged in and interoperate in a "Smart Building" without undue difficulty. The CAL defines how devices interact. The Home PNP Specification defines things such as home states (e.g. Unoccupied). The CAL and Home PNP Spec do not depend on a specific transmission technology. However, devices using incompatible transmission technologies are likely to have some difficulty communicating.

Many US homes are wired with two 117 volt (nominal) signals 180 degrees out of phase with each other. Unless there is a full time on "220 volt" device in the house, the only common element is the ground, it is not clear how signals are to propagate between the two sets of circuits.

CEBus seems to be the current core technology for "smart buildings" whose potential has long been acknowledged, but whose realization has been slow to arrive.

Return To Index Copyright 1994-2002 by Donald Kenney.