6 May
2008
6 May
'08
8:53 p.m.
On Tue, 06 May 2008 07:53:52 -0500 Jules Richardson wrote:
Actually the X10 home automation system is quite reliable as its
longevity attests. Currently, broadband over power is being deployed
in a number of test cities in the US (much to the chagrin of Hams - it
tends to raise the noise floor in ham bands excessively) and the usual
suspects are peddling home networking over the mains (e.g.
<http://www.dlink.com/products/?sec=1&pid=561d
Jules
Richardson noted:
Ahh, no - on that note I meant 'mistrust' as in reliability. Running
data over
power lines always seems like the sort of thing that'd work in the
lab, but be
a little unreliable out in the real world with all sorts of 'noisy'
devices
plugged into the system.
[...] Hmm, I've got a deep mistrust of any
'data over the mains'
technology, but
might that be an option here? I assume *most* of your systems are
physically
plugged into the mains anyway, so it'd meet the ideal requirement
for no extra
cabling. Data rates presumably not lightning fast, of course...
I don't think security is of concern here unless you are extremely
paranoid or are transferring prohibited material [...]. ).
To get around the noise issue, these systems use burst transmission at
the zero voltage crossing point when line noise is statistically the
least.
As I mentioned previously, a number of folks make transceivers for
this purpose. Echelon <www.echelon.com> has made their entire business
based on this technology used mainly in commercial applications.
<http://www.powerlinenetworking.co.uk/component/option,com_frontpage/Itemid,1/
is a UK firm pushing the technology locally.
IC transceivers are available from ST, Maxim, and SiConnect. The
addition of a small micro to do the RS232, support logic, and power
supply should make a useable system meeting Tony's requirements.
CRC