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Aerophilic — Fri, 22 May 2009 20:57:08 GMT

Aerophilic:

Welcome to the RXTX wiki!

This Wiki is intended to be by and for RXTX users and developers. There is already a lot of information provided, but feel free to add your own content. Note that you will need to create an account before editing pages, as part of an effort to battle spambots.

*[http://www.rxtx.org Old RXTX home page] This wiki will be the RXTX Home Page when 2.2 is released.
*[[FAQ]]
*[[Download]] and [[Installation]]
*[[Using RXTX]]
*[[Development]]
*[http://bugzilla.qbang.org Reporting Bugs]
*[[Projects | Projects using RXTX]]
*[http://users.frii.com/jarvi/rxtx/license.html License] LGPL v2.1 + Linking Over Controlled Interface.
If after checking through the Wiki you don't find an answer to your question, then you can ask your question on the [[mailing-list]]. Posting questions in the talk pages is not the right place to ask your questions.

There is also the [http://users.frii.com/jarvi/rxtx/ original RXTX website], which is still around, though most of the information has been migrated to the Wiki.

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FAQ

Aerophilic — Fri, 22 May 2009 20:56:42 GMT

Aerophilic:

== General ==

=== What is RXTX? ===

RXTX is a Java library, using a native implementation (via JNI), providing serial and parallel communication for the Java Development Toolkit (JDK). All deliverables are under the GNU LGPL license. It is based on the specification for Sun's [http://java.sun.com/products/javacomm/index.jsp Java Communications API], though while many of the class descriptions are the same the package used it not, since gnu.io is used instead. A certain amount of compatibility is intended with API, though this project should be considered as a fork and therefore compatible in spirit, but not in implementation.

=== Do you have a Mailing List? ===

Yes, see the [[mailing-list]] page for details.

=== Where can I find information about how to write apps using RXTX? ===

Take a look at the [[Examples]]

=== What does RXTX install where? ===

The RXTX installation procedures installs files directly underneath $JAVA_HOME, i.e. directly into the JDK distribution.

In case you are using the Sun JDK:

The 'gnu.io' Java .class files are all packed into:

$JAVA_HOME/jre/lib/ext/RXTXcomm.jar

The [http://en.wikipedia.org/wiki/Library_(computer_science)#Shared_library Shared Object] files necessary to access OS-level functionality can be found underneath:

$JAVA_HOME/jre/lib/<architecture>/

and they are:

librxtxI2C-2.1-7.so
librxtxI2C.la
librxtxI2C.so -> librxtxI2C-2.1-7.so

librxtxParallel-2.1-7.so
librxtxParallel.la
librxtxParallel.so -> librxtxParallel-2.1-7.so

librxtxRaw-2.1-7.so
librxtxRaw.la
librxtxRaw.so -> librxtxRaw-2.1-7.so

librxtxRS485-2.1-7.so
librxtxRS485.la
librxtxRS485.so -> librxtxRS485-2.1-7.so

librxtxSerial-2.1-7.so
librxtxSerial.la
librxtxSerial.so -> librxtxSerial-2.1-7.so

Also see the '[[installation]]' page for more information.

=== Is there a Change Log? ===

Yes, see the '[[Change Log]]' page.

=== What License does RXTX use? ===

RXTX is license under the LGPL with an exception for linking over controlled interfaces, a copy of which can be found in the '[[License]]' page. The exception allows people to use RXTX as a service plugin with Sun's CommAPI: 'A Controlled Interface.'

=== What Platforms does RXTX run on? ===

See the page entitled '[[Porting]]', for more information.

== Problems and Workarounds ==

=== On MacOS X I get a 'PortInUseException', even though it isn't? ===

Versions prior to 2.1-8 use lock files, which is not the MacOS X way of doing things, and therefore has issues. For this reason make sure that you have version 2.1-8 or higher, which makes use of [http://developer.apple.com/documentation/DeviceDrivers/Conceptual/IOKitFundamentals/ I/O Kit]. At this point in time 2.1-8 is only availble from CVS, in source form. See the section [[Retrieving Source Code]], on getting the latest code - be sure to get the code from the 'gnu.io' branch.

'TODO': Can anyone who knows how please make an easy download available like the 2.1-7 version?
There you go: http://www.mediafire.com/download.php?zx1hlhghyyh
'TODO': Can anyone who knows how please upload this file to rxtx.org?

=== RXTX does not find my device, what's wrong? ===

There may be a number of reasons, but most often it is because your operating system can't find it either. RXTX is built upon the functionality provided by your operating system, and therefore is dependent on its limitations. For this reason find out whether your system can find the port, if it can and you still can't work what is going on, then there may be some help on the [[Mailing-List]].

You can specify the available ports by
System.setProperty("gnu.io.rxtx.SerialPorts", portFileNames);
where the file names of the ports are separated by File.pathSeparator.

=== RXTX installation fails with JDK 1.6 ===

This applies to the source package of RXTX 2.1-7r2.

After having run ''./configure; make; make install'', the following message appears:

make all-am
make[1]: Entering directory `/<mumble mumble your directory>/rxtx-2.1-7r2'
make[1]: Nothing to be done for `all-am'.
make[1]: Leaving directory `/<mumble mumble your directory>/rxtx-2.1-7r2'
libtool: install: `x86_64-unknown-linux-gnu/librxtxRS485.la' is not a directory
Try `libtool --help --mode=install' for more information.
make: *** [install] Error 1

This is caused by a missing case in the 'configure' script generated from 'configure.in', which
causes the variable RXTX_PATH to not be set which causes the above confusion.
You can change the 'configure' script directly. Look for the case instruction that matches JDK version strings:

1.2*|1.3*|1.4*|1.5*

and extend it to

1.2*|1.3*|1.4*|1.5*|1.6*

Note that there are matches for Linux, BSD, Solaris and Win32.

Then run ''./configure; make; make install'' as usual.

=== RXTX and the Equinox SST-4P/LP multiport card ===

A note for those who want to install an Equinox board (in this case "SST-4P/LP") and try to
run it with RXTX under Linux (in this case, Red Hat ES 4)

Get the driver source from the [http://www.equinox.com/support/download-drivers/ www.equinox.com driver page] and
compile it as described therein.

The four serial ports of the Equinox SST-4P are available as the device files:

/dev/ttyQ1a1 ... /dev/ttyQ1a4

These device files are created by the 'ssmkn' (alias 'make device nodes') executable.

In order to make things work, you have to:

Modify the 'eqnx' startup script '/etc/rc.d/init.d/eqnx'
and make it set the permissions of the devices files in the
'start' section, immediately after the call to 'ssmkn':

# create device files
/usr/bin/ssmkn
# fix rights on device files
LIST=`ls /dev/ttyQ*`
for DEV in $LIST; do
chown root.uucp $DEV
chmod 660 $DEV
done

Modify 'src/RXTXCommDriver.java' in the RXTX distribution. Add
the 'ttyQ1a' radical to the list of port radicals that RXTX checks:

if(osName.equals("Linux"))
{
String[] Temp = {
"ttyS", // linux Serial Ports
"ttySA", // for the IPAQs
"ttyUSB", // for USB frobs
"ttyQ1a" // Equinox
};
CandidatePortPrefixes=Temp;
}

Then recompile and reinstall.

=== Is there a way to access serial and parallel port with standard Java API ? ===

Currently no. This includes all Java versions including JDK 1.6 and probably JDK 1.7 when it is released. The [http://java.sun.com/products/javacomm/ Java Communications] API is a Java extension providing the necessary support for serial and parallel communication. RxTx is the most complete and currently maintained implementation of this API.

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