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 From: Doug Mosher
 Subject: More X10 questions

 To: sci-electronics@ucbvax

 rlf@mtgzy.UUCP (XMRN10000 saf -r.l.fletcher) asks:
 >but what is lacking in this system is feedback to a host. I cannot
 >help but wonder why no company (BSR, Tandy, GE, Leviton) has done any kind
 >of development on adding feedback from the modules to a host controller.
 >It does not seem to me an insurmountable problem.

 >Why has this not been done (or has it).

 Actually, it has been done but was not a market success. I can't recall the
 company name, but I was studying all developments in the period 1982-84 and
 one company added several twists. They had modules completely compatible with
 X-10, and also modules that communicated with an FSK-style code, also done by
 modulating rf on the house power lines. Some of their modules sent status info
 back to "the host". I also remember discussion of a drawback to this: there
 were twice as many failure modes (a regular module responds or it doesn't;
 these responded or not, and said they did or not, sometimes independently.)

 I am personally a devotee of buy-a-module home automation. But that has proved
 to be a very thin market. It seems that most people fall into the "consumer"
 category, and want really simple (read on-off) devices. Then a few people are
 hobbyists and are willing to wire up gizmos to do neat things (many of us
 sci.electronics readers, for example). Even fewer people want to do the fancy
 functions, by buying things off the shelf.

 So it has been a minor miracle that any convention evolved, and that it has
 lived in a continually available, upward compatible way for years; namely the
 X-10 family. It seems to me that its inventors just stuck doggedly to the
 grindstone, perhaps 10 years now, until a critical mass of devices gained
 their way into homes. (And they have short chip lives, so it has taken
 replacement sales to keep up the critical mass...). But it's very difficult
 for anyone else to join the fray. Even attempts to "marry" the existing
 technology have failed miserably; General Electric spent a big wad on the
 homeminder, only to have to sell it off bankruptcy-style to that
 all-encompassing sponge for selloff technology, Radio Shack.

 I wish it were otherwise, but am glad there is at least some technology in
 this niche that stays living. Incidentally, the main companies that share the
 X-10 standard and patents, BSR and Leviton, have taken many knocks themselves.
 BSR put out a whole series of home-computer interfaces, only to have to sell
 them for peanuts thru DAK mailorder soon thereafter.

 (                                                            )
 (          Doug Mosher <SPGDCM@CMSA.Berkeley.edu>            )
 ( 257 Evans, Univ. of California, Berkeley, CA, 415/642-5823 )
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