19
Appendix D
Software License Agreement
12 Volt Power Over Ethernet Adapter Kit
GNU LESSER GENERAL PUBLIC LICENSE
Version 2.1, February 1999
Copyright (C) 1991, 1999 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
USA
Everyone is permitted to copy and distribute verbatim
copies of this license document, but changing it is not
allowed.
[This is the first released version of the Lesser GPL. It also
counts as the successor of the GNU Library Public License,
version 2, hence the version number 2.1.]
Preamble
The licenses for most software are designed to take away
your freedom to share and change it. By contrast, the GNU
General Public Licenses are intended to guarantee your
freedom to share and change free software—to make
sure the software is free for all its users.
This license, the Lesser General Public License, applies to
some specially designated software packages—typically
libraries—of the Free Software Foundation and other
authors who decide to use it. You can use it too, but we
suggest you first think carefully about whether this license
or the ordinary General Public License is the better strategy
to use in any particular case, based on the explanations
below.
When we speak of free software, we are referring to
freedom of use, not price. Our General Public Licenses
are designed to make sure that you have the freedom
to distribute copies of free software (and charge for this
service if you wish); that you receive source code or can
get it if you want it; that you can change the software and
use pieces of it in new free programs; and that you are
informed that you can do these things.
To protect your rights, we need to make restrictions that
forbid distributors to deny you these rights or to ask you
to surrender these rights. These restrictions translate to
certain responsibilities for you if you distribute copies of
the library or if you modify it.
For example, if you distribute copies of the library,
whether gratis or for a fee, you must give the recipients
all the rights that we gave you. You must make sure that
they, too, receive or can get the source code. If you link
other code with the library, you must provide complete
object files to the recipients, so that they can relink them
with the library after making changes to the library and
recompiling it. And you must show them these terms so
they know their rights.
We protect your rights with a two-step method: (1) we
copyright the library, and (2) we offer you this license,
which gives you legal permission to copy, distribute and/
or modify the library.
To protect each distributor, we want to make it very clear
that there is no warranty for the free library. Also, if the
library is modified by someone else and passed on, the
recipients should know that what they have is not the
original version, so that the original author’s reputation
will not be affected by problems that might be introduced
by others.
Finally, software patents pose a constant threat to the
existence of any free program. We wish to make sure
that a company cannot effectively restrict the users of
a free program by obtaining a restrictive license from a
patent holder. Therefore, we insist that any patent license
obtained for a version of the library must be consistent
with the full freedom of use specified in this license.
Most GNU software, including some libraries, is covered
by the ordinary GNU General Public License. This license,
the GNU Lesser General Public License, applies to certain
designated libraries, and is quite different from the
ordinary General Public License. We use this license for
certain libraries in order to permit linking those libraries
into non-free programs.
When a program is linked with a library, whether
statically or using a shared library, the combination of
the two is legally speaking a combined work, a derivative
of the original library. The ordinary General Public
License therefore permits such linking only if the entire
combination fits its criteria of freedom. The Lesser General
Public License permits more lax criteria for linking other
code with the library.
We call this license the “Lesser” General Public License
because it does Less to protect the user’s freedom than
the ordinary General Public License. It also provides
other free software developers Less of an advantage over
competing non-free programs. These disadvantages are
the reason we use the ordinary General Public License
for many libraries. However, the Lesser license provides
advantages in certain special circumstances.
For example, on rare occasions, there may be a special
need to encourage the widest possible use of a certain
library, so that it becomes a de-facto standard. To achieve
this, non-free programs must be allowed to use the library.
A more frequent case is that a free library does the same
job as widely used non-free libraries. In this case, there is
little to gain by limiting the free library to free software
only, so we use the Lesser General Public License.
In other cases, permission to use a particular library in non-
free programs enables a greater number of people to use
a large body of free software. For example, permission to
use the GNU C Library in non-free programs enables many
more people to use the whole GNU operating system, as
well as its variant, the GNU/Linux operating system.
Although the Lesser General Public License is Less
protective of the users’ freedom, it does ensure that the
user of a program that is linked with the Library has the
