Subject:
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Re: Serial interface/ RF data link
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 8 Dec 1998 18:42:03 GMT
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Original-From:
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Darkman <lroska@[StopSpam]cyberus.ca>
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Viewed:
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1218 times
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To properly comunicate with any PC you need to convert your TTL TX and TTL
RX signals coming from the Handy Board to RS232 voltage levels. The charging
board contains this interface IC called the "MAX232"
The power wire is required unless you are willing to power the Serial
interface board from a separate wall adapter and you definetly require the
ground wire because this is the common ground return for both the TX and RX
lines.
You need power to supply the MAX232 IC!
As for your second question I assume that most of these RF links require
only TTL level TX and RX signal and a common ground to work so there is no
need to use the charging board at all.
I hope this helps.
ann-Original Message-----
From: DjKOz97@aol.com <DjKOz97@aol.com>
To: handyboard@media.mit.edu <handyboard@media.mit.edu>
Date: Tuesday, December 08, 1998 1:10 PM
Subject: Serial interface/ RF data link
> Let's say I want to use a serial interface board without the "charger", as • the
> one provided with the Handyboard kit. The Tx and Rx lines are obviously
> required, but what about the ground and power lines?...
> Speaking of "easy to interface" data link solutions, I have a kit from Lynx
> Technologies which is supposed to provide a wireless two way voice/ data • link.
> All that you need to provide is the tx/rx data. The kit has 2 tx, 2 rx • modules
> and RS232 interfaces on 2 development boards (for 2 way communication) it • also
> includes 2 antennas. I had to order another pair in order to provide the 2 • way
> data link.
> Unfortunately, I have not had any luck. This brings me back to the first
> point- is it possible to use the serial interface board by just providing • the
> tx and rx lines?
> I took a spare modular phone cable and tested it with the Handyboard's • serial
> interface board to make sure it worked... It did. Next, I cut it in half • and
> exposed the 4 wires. Judging from the schematic in the Handyboard manual, • the
> yellow wire is the rx line, the green is ground, the red power, and black • is
> the tx line. So I reconnected the tx and rx lines, and tried to run ic. • When I
> did, I got the message "Board disconnected or not responding". I then
> reconnected the ground wire, but got the same message. It was only when I
> reattached the red power wire that ic finally loaded successfully.
> I guess my question is- with any of the wireless link solutions suggested, • how
> can we provide just the tx and rx data, without using the ground and power
> lines? Or, at the very least, without the power line? ( Ground can be • provided
> from the receiver board).
> Thanks again,
> Dave
>
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