At 07:34 AM 10/8/97 -0500, Jim Choate thoughtfully expounded thus:
The trick with X-10 is to stay away from transformers as the signal won't go through them effectively. This ends any dreams of sending data to your neighbor, the signal won't go through your power meter.
Ahh, the memories this brings back!
I once worked for a large hosiery manufacturing company that markets its
products in a little egg-shaped container, which to protect the stupid,
shall remain unnamed.
Around 1979, they wanted to automate the collection of manufacturing
information on the shop floor using terminals available to the slaves (Err,
I mean piecework workers), and some bright lad had the idea of impressing
the signal on the power supply in the factory. This was OK until they
found out that they drew three separate 110 volt runs off of their
three-phase main supply, and the signal wouldn't make it from one run to
the other, this dividing the system up into three non-communicating
separate networks.
This was shelved, and the hand-built data collection terminals were
reworked to plug into coax instead. Unfortunately they then decided on a
ring topology for the network linking all the little hand-built terminals,
combined with a sequential polling system that wouldn't skip a terminal if
it didn't answer!!!
This lead to one of the more interesting periods in my life, spending six
months every other week in a Southern textile town baby-sitting little grey
boxes. When one quit working, I had to make a tour of the network loop,
resetting little gray boxes until the network came back up again. The fact
that workers sewing pantyhose build up incredible static electric charges
didn't help matters any, and lead to cryptic instructions to the workers to
touch the metal terminal stand before entering any information into the
system!! One can only imagine the Pavlovian effects this had on worker
acceptance of this new, improved data collection system.
Ten years ago, the little grey boxes were gathering dust in a storage room.
Five years ago, I could not find anyone who recalled working on this
project(!)
Tom Porter txporter@mindspring.com
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"On two occasions I have been asked [by members of Parliament],
'Pray, Mr. Babbage, if you put into the machine wrong figures, will
the right answers come out?' I am not able rightly to apprehend the
kind of confusion of ideas that could provoke such a question."
FIGHT U.S. GOVT. CRYPTO-FASCISM, EXPORT A CRYPTO SYSTEM! RSA in PERL:
print pack"C*",split/\D+/,`echo "16iII*o\U@{$/=$z;[(pop,pop,unpack"H*",<>
)]}\EsMsKsN0[lN*1lK[d2%Sa2/d0