pertd2/LICENCE.md

No idea about the licence.

The only ref i've found about is in the Device::Pertelian perl module from cpan

Device-Pertelian

Device::Pertelian - a driver for the Pertelian X2040 USB LCD.

INSTALLATION

To install this module, run the following commands:

	perl Build.PL
	./Build
	./Build test
	./Build install

SUPPORT AND DOCUMENTATION

After installing, you can find documentation for this module with the
perldoc command.

    perldoc Device::Pertelian

You can also look for information at:

    RT, CPAN's request tracker
        http://rt.cpan.org/NoAuth/Bugs.html?Dist=Device-Pertelian

    AnnoCPAN, Annotated CPAN documentation
        http://annocpan.org/dist/Device-Pertelian

    CPAN Ratings
        http://cpanratings.perl.org/d/Device-Pertelian

    Search CPAN
        http://search.cpan.org/dist/Device-Pertelian


COPYRIGHT AND LICENCE

Copyright 2008 Alex Kapranoff, all rights reserved.

This program is released under the following license: GPL3

In the included pertd.tgz archive there is code by:
Frans Meulenbroeks, Ron Lauzon, Pred S. Bundalo, Chmouel Boudjnah,
W. Richard Stevens.

The code in pertd.tgz is either in Public Domain or available for
distribution in unmodified form. See the relevant files.

It suggests that the code is at least Public Domain.