Re: [ha] wired home network using CAN

Dan McDaid (
Wed, 25 Aug 1999 22:40:59 +0100

In message <006101beef3b$b6a491a0$>, Steve Letkeman
<> writes
>Hi All,
> It's been so long since I subscribed to this mailing list
>that I'm not exactly sure what it's focus is on so if this
>thread is out of line than let me know.
> There is talk about power line modems, X10 and RS-485
>but I want to open another thread, and that is the use of
>CAN for hardwired home control. I am currently using X10
>for a few lights and find it just to slow and unreliable. I
>don't mind running wires if it gives me crisp response and
>reliability. RS-485 is a good choice because any micro
>can run an RS-485 port but since I spend all my professional
>time developing CAN devices, I'm very biased at this point.
> For those that don't know what CAN is, it stands for
>Controller Area Network and is a hardware device that
>is added to a number of micro's (internally or externally)
>that provides very, very robust communication over
>twisted pair cabling at speeds up to 1Mbps (40m max).
> The hardware looks after all the transfer of information,
>leaving the fun stuff for the user. This significantly reduces
>the software needed compared to RS-485 and allows
>a multi-master system. There are a number of low cost
>CAN micros including the Siemens C505C and various
>Motorola HC05's HC08's etc.
> I already have a number of CAN nodes running in my
>house monitoring and controlling various devices so I'm
>not really looking to start an argument over whether
>CAN should be used Vs. RS-485 because both have
>various pro's and con's, rather, this is a long winded
>attempt to find out if anybody is interested in developing
>a CAN based, open spec'd, home automation system.
>Steve Letkeman
>Zanthic Technologies Inc. located at
>Controller Area Network boards for HC11, ISA/PC104 and Parallel
>I/O boards for ISA and Parallel, Win95/98 and NT drivers included

I can honestly say I've never heard about this - except for reading your
earlier threads when this list was opened.

I'm open to anything - I agree with you when you infer that RS-485 is
not fast enough, for that matter, Powerline modems are even worse - but
as you say they all have their place. CAN does sound interesting - as
for it looking after transfer of information that sounds very good. I
assume that by this you mean that it waits for clear line - is it full
duplex ?

As I say - I'm interested in pursuing this as I know you are keen to.
Perhaps you could advise me of some decent reading material on the topic