Long-range RF transceiver modules...

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    I hope this is the right forum to ask this...  :-)

   I'm doing some preliminary work (thrashing around...?) on a project
that will be set up as a wireless network.  I need a transceiver that
will operate with an approximately 10,000-foot range.  From what I've
been able to determine, the best way to get that kind of range is with
a Spread-Spectrum system.  Unfortunately, the only ones I've been able
to find (MaxStream and AeroComm) only support 8-bit data transfers...
and I'm looking at using the 9-bit addressing mode in 8051-series
microcontrollers to do module-recognition.

   Can someone point me in the right direction, to find wireless
modules that don't limit the design to simple serial data...?  Linx
modules look good, but they don't have the kind of range I'm looking
for, even when boosted with an RF amplifier.


Re: Long-range RF transceiver modules...
Why not use escape sequences (like SNMP)
instead of 9 bit addressing used by 8051 family.
Only a very few 8051 families (FX) actually
have address recognition ability.

Here is another link with SS technology.
http://www.cirronet.com/industrial.htm


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Re: Long-range RF transceiver modules...

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   Because I'm not a very sophisticated programmer, so I like to keep
things straightforward.  :-)

   Thanks for the link.


Re: Long-range RF transceiver modules...

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Implementing escape sequences is much easier than you would think.

Here is an some text from this link:
http://www.trio.com.au/technote/Tn-8n.PDF

The asynchronous serial channel to be used must be configured for eight bit
character size, no parity, and one stop.

A specific binary code called FEND (Frame End, hexadecimal valueC0%) is
reserved to define a frame boundary. Should this
same code occur in the data message to be transferred across the channel
controlled under SLIP, then an escape sequence
is used so that the message byte will not be confused for a FEND. This
escape sequence, involves replacing the message
hexadecimal C0 code with a two byte sequence FESC, TFEND. FESC (Frame
Escape) is the binary code hexadecimal DB,
and TFEND (Transposed FEND) is binary code hexadecimal DC. Likewise, if the
FESC character ever appears in the user
data, it is replaced with the two character sequence FESC, TFESC (Transposed
FESC). The TFESC is the binary code
hexadecimal DD. The following table clarifies this.

ABBREVIATION DESCRIPTION HEX.VALUE

FEND Frame end C0
FESC Frame escape DB
TFEND Transposed frame end DC
TFESC Transposed frame escape DD

As characters arrive at the SLIP receiver, they are appended to a buffer
containing the current frame. Receiving a FEND marks
the end of the frame, and consequently, succeeding bytes are considered part
of the next frame.
Receipt of a FESC code puts the SLIP receiver into "escaped mode", causing
it to translate a following TFESC or TFEND back
to a FESC or FEND code, appending it to the buffer, and resuming it's normal
state. Receipt of any byte other than TFESC or
TFEND while in escaped mode, is an error. No translation occurs, and the
SLIP receiver leaves escaped mode. A TFESC or
TFEND received while not in escaped mode is treated as an ordinary character
and stored accordingly. Reception of
consecutive FEND characters, causes no action to be taken (i.e. is not
interpreted as zero length frames).
An example of a typical SLIP frame is shown below. The message consists of
the string DA,C4,C0,C5,DB,20,BD,DC,DD.
The SLIP frame will be:-

<FEND>,DA,C4,<FESC>,<TFEND>,C5,<FESC>,<TFESC>,20,BD,DC,DD,<FEND>
==> C0,DA,C4,DB,DC,C5,DB,DD,20,BD,DC,DD,C0



Re: Long-range RF transceiver modules...

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Check the SS-200 at <http://www.apexwireless.com/ .
The data format can be selected as either 8 or 9 bit.

Disclosure: This is a client.

Thad

Re: Long-range RF transceiver modules...
check http://www.aerocomm.com/ they have what you need

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