Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!umd5!purdue!gatech!hao!oddjob!gargoyle!ihnp4!ihlpe!psfales
From: psfales@ihlpe.ATT.COM (Pete Fales)
Newsgroups: sci.electronics
Subject: Re: X10 specs/parameters
Message-ID: <2648@ihlpe.ATT.COM>
Date: 16 Feb 88 14:58:58 GMT
References: <960@ur-tut.UUCP>
Distribution: na
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 35
Keywords: x10 BSR Leviton remote automation

In article <960@ur-tut.UUCP>, syap@ur-tut.UUCP (James Fitzwilliam) writes:
> Are parameters for the X10 system publicly available, if so, where?  i.e.
> what must be broadcast on the AC line for "Unit E-15 / Dim / All off"  I'm
> interested in a telephone controller that would respond to touch-tones,
> but since I have the Powerhouse I would rather not get the Homeminder, so:

The May, 1985 issue of Byte had an article called  "Build The Home Run 
Control System - Part 2: The Hardware"  by Steve Ciarcia.  This article
included a detailed description of the signals that are sent over the AC
line and included schematics for some hardware to generate them.

> 
> Are ROM or other chips with the X10 command set available for purchase?  It
> would be amazingly simple to buy a chip for the X10 controls, hook it up to
> a tone decoder, and - presto - telephone response.  (Or are the chips off
> limits to prevent people from doing exactly that?)

If you find any let me know!

> A general electronics question: Since I've never actually seen a design for
> a carrier-current operated device, I'm curious as to how the transmitter is
> isolated from the high-voltage AC on the "antenna" i.e. the line cord.

See the above mentioned article.  As I recall (working from memory now)
Steve was understandably concerned about builder safety and chose an
approach involving a custom isolation transformer.  There are probably
cheaper approaches that could be used in high-volume sealed boxes like
the BSR units.  Obviously, anything involving a direct interface to 120VAC
should be approached with a great deal of care.

-- 
Peter Fales		UUCP:	...ihnp4!ihlpe!psfales
			work:	(312) 979-7784
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