CEBus Technology: A Home Automation Standard Explained

This article provides a comprehensive overview of CEBus technology, outlining its basics and exploring its use in IoT (Internet of Things) based home automation.

CEBus stands for Consumer Electronic Bus. It’s a communication standard defined by the EIA (Electronic Industries Alliance) that allows electronic products within a home to communicate with each other using six different media.

CEBus Physical Media

The physical media used to transmit signals within a CEBus network are:

• Power Line Bus
• Infrared
• Radio Frequency Bus
• Twisted Pair Bus
• CoaX Bus
• Fiber Optic Bus

Essentially, CEBus can be considered a LAN (Local Area Network) specifically designed for home automation purposes.

CEBus Fundamentals

CEBus operates as a packet-oriented, connectionless, peer-to-peer network. It uses the CSMA/CDCR (Carrier Sense Multiple Access with Collision Detection and Collision Resolution) protocol for managing network traffic.

The first version of the CEBus standard, known as IS-60, was released in 1992 and subsequently revised in 1993/1994.

CEBus-compatible products typically consist of two main components: a transceiver and a microcontroller.

Commands within a CEBus network, such as “fast forward,” “volume up,” “rewind,” “pause,” and “temperature up/down,” are developed using CAL (Common Application Language).

CEBus supports two distinct types of channels:

• Control Channel: Used for connection-oriented functions.
• Data Channel: Used for intensive data transfer.

CEBus Technology Features

CEBus Protocol Stack

Figure 1: CEBus protocol stack

The CEBus protocol stack, as illustrated in Figure 1, maps to four layers of the OSI (Open Systems Interconnection) model:

• Physical Layer
• Data Link Layer
• Network Layer
• Application Layer

CEBus defines the physical characteristics of the various media used and specifies the application language interpreter.

CEBus Packet Structure

Figure 2: CEBus packet structure

Figure 2 shows the CEBus packet structure for RF (Radio Frequency) and Powerline media. The structure is as follows:

CEBus packet = {LPDU(Link Protocol Data Unit), NPDU(Network Protocol Data Unit) , APDU(Application Protocol Data Unit), CAL message, CRC}

The size of a CEBus packet can vary from approximately 50 bits to about 350 bits, depending on the size of the CAL message and the content of the headers.