On the Buses: Last station still far off 1

Published:2011/8/9 21:24:00 Author:Amy From:SeekIC

David Daamen

Being able to control a TV or a stereo from the comfy chair is taken for granted these days. However, home automation does not stop at remote control for audio & video equipment. Although an increasing number of manufacturers jump the bandwagon called Home Automation or even the Smart Home, there are no signs as yet of a real breakthrough ’for the millions’.

Although several systems are currently available on the market to automate various functions in and around the home, the large number of different, competing, standards and proprietary developments is a large stumbling bock on the road towards the Home of the Future. In an earlier issue we wrote that developments in home automation were being slowed down by the possibilities and impossibilities of facility engineering (’Home Bus Sys-terns’, Elektor Electronics February 2001). Apparently, developing and marketing a compatible system is time consuming to the extent that manufacturers are always one step behind reality.

One of the main problems seems to be flaky exchange of data between different applications. Once the main hitches have been recognized, it is often impossible to make amends at the high pace that rules in the electron­ics industry. This situation has resulted in a plethora of different protocols and standards which only seems to aggravate the problem.

Lessons have been learned, however, because today the trend is not just to look at the connection method, but increasingly at the actual application.

OSI

The fact that it has taken so long for the system designers to spend time on the application is not surprising in itself. Since the mid-1980s, there exists a standard describing the aspects to take into account when implementing the network functionality. At that time, the ISO (International Standards Organization) published a reference model called Open Systems Interconnect (OSI), see Figure 1. A bit further on, we’ll see that besides many standards concentrating on the actual connection and/or the man­ner of communicating, there are now also standards giv­ing due attention to the highest layers of the OSI model: the area where the actual application is concerned. For convenience’s sake, we will divide the standards (professional networking and home automation) into three categories derived from the OSI reference model. The subdivision is into (1) the network layer; (2) the com­munication layer and (3) the application layer.

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