Subject:
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Re: Thanks fro the reply...
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 11 Aug 1997 19:08:22 GMT
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Original-From:
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Chuck McManis <cmcmanis@!saynotospam!FreeGate.net>
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Reply-To:
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cmcmanis@freegate.net*Spamless*
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Viewed:
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1523 times
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At this point we're not quite into Handyboard questions, but since the
answer
might help others, here goes...
German Gentile wrote:
> Your answer is very useful for my, but i don't know very well the
> RS-422.
> Where i can more info about that???
German, the world wide web is an amazing thing. The most amazing part
isthe amount of information that is available on it. I took your
question and
typed it into the web site AltaVista.
(http://www.altavista.digital.com/)
As the search criteria I typed in two words "rs-422 faq" (FAQ is the
short form of "Frequently Asked Questions") it turned up several
resources
on the Web (over 13,000 to be exact), the very first one was this one:
1. DataReach FAQ, RS-232 & RS-422 Connectivity Frequently Asked
Questions
DataReach™ FAQ. How can I direct multiple RS-232 data, Bar Code
readers, POS or other serial outputs into a single COM port? The SDC-61
Serial Data...
http://www.westtel.com/drfaq.htm - size 5K - 8-Apr-97 - English
Sounds exactly like what you are doing yes?
> Well , imagine i use a rs-232 connection, between all the handys (in
> parallel) and the PC.
No, the correct physical layer protocol to use is RS-422, not RS-232.
Bothfor distance and for multiple boards per line.
> I'm thinking add a line to the wires to the handys,
> Later, I'm send a message to all the handys (in parallel via the
> rs-232 in
> the interface charger) , the header say who get this message (each
> handy
> have a id unique). In the inverse way, a handy test this additional
> wire,
> if is high the bus is busy, else (wire is low ) send the message with
> a
> header saying "Hey PC , i'm the handy 5 " or the Handy 4 or other.
> It's ok
> or not ???
That will work fine, you don't need an additional wire. Simply monitor
the bus
and if you see a start bit, hold off one byte time and sample again.
Further if
the protocol is half duplex (ie send command, wait response) you won't
get
any contention anyway.
Can I strongly encourage you to use the Web Search sites to try to find
answers
to your questions before you pose them to the list? That helps keep the
signal
level in the mailing list high as the questions are those that can only
be answered
by people using Handyboards.
Not a flame, just a friendly request.
--Chuck
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Message is in Reply To:
 | | Thanks fro the reply...
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| Well, so thanks fro your reply, you make feel live. You are rigth , Fred are right and so chuck are rigth.I'm very obsesive and may be not exist a answer short to my questions , sorry for my self. Your answer is very useful for my, but i don't know (...) (27 years ago, 11-Aug-97, to lugnet.robotics.handyboard)
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