PC Card!?!

Jim Carter jimc at math.ucla.edu
Thu Mar 28 08:02:14 EST 2002

On Wed, 27 Mar 2002 ivanguidelli at zipmail.com.br wrote:
> My name is Ivan Guidelli, work in a company of industrial automation in
> Brazil and is participating of a design for collection of data with wireless
> communication. This communication will be made through a card PCMCIA or
> PC Card, as to want to call, made a market research and is wanting to work
> with any types of antenna and mark, external or internal, 3Com, Symbol,
> Orinoco, D-Link, etc, but I am with difficulty in knowing if already drive
> for Linux and/or Windows that obtain to congregate, to the maximum exists
> some, all the features above cited. It would like some suggestion, already
> they work in the branch has much more time that I.

At present the Linux drivers for Cisco-Aironet and Orinoco (and various OEM
clones of Orinoco, such as Dell, Linksys, D-Link) are working pretty
reliably.  The cards all come with Windows drivers, which work, as far as
I've tried them.

At UCLA we have a wireless net installed for testing, with access points in
the library and a neighboring food facility. It works reasonably well.
However, equipment (ovens and refrigerators) blocks the signal, as do
metal bookshelves, so there are areas that they wanted to cover but where
the signal is too low.  A similar problem would occur in a factory
situation.  Also, when people walk in front of the antenna or leave boxes
of metal parts in the path, the signal can be lost temporarily.  The
software would have to tolerate lost packets.

For factory automation, a combination of wired Ethernet to machines in a
fixed location, plus wireless devices carried by the workers, might be
best. For safety, be sure to run the data lines in a separate conduit from
the power, even though this doubles the cost of installation. Also,
common-mode power surges can be a problem: when a big machine turns on or
off, voltages are induced in the Ethernet, which could be beyond the safe
limits of the Ethernet card. Rigid metallic conduit (expensive to install)
helps reduce interference. If the client's budget allows, fiber optics is
immune to such interference.

> Radar UOL - http://www.radaruol.com.br

By the way, I tried to check on your products, but www.radaruol.com.br
seems to be a CNAME for amazonas.uol.com.br which has no "A" record.  You
might want to bring this to the attention of your sysop.

James F. Carter          Voice 310 825 2897    FAX 310 206 6673
UCLA-Mathnet;  6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA  90095-1555
Email: jimc at math.ucla.edu    http://www.math.ucla.edu/~jimc (q.v. for PGP key)

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