The collection of LoCosto firmware source and documentation that came from the
Peek company (see the main README file in this directory) contains among other
things a documentation directory tree named PSL1DOC.  The documents contained
therein describe various aspects of TI/Condat's GSM/GPRS protocol stack
implementation in considerable detail.  But unfortunately most of these
documents (in the original ware) are in the proprietary Micro$oft Word format,
making them difficult to read.

A member of the FreeCalypso project has been able to extract the document
content from those M$ Word files and convert them into both plain text and PDF.
PSL1DOC.tar.xz contains the original PSL1DOC directory tree, with all of the
original files intact, plus the converted *.txt and *.pdf for every original
*.doc document.

2015-03-15 addendum: the volunteer who did the PSL1DOC format conversion was
working from the LoCosto-scottn-peek-ware.tar.xz version, as it was prior to
our discovery of the original version from Peek.  Therefore, Perl script
PSL1DOC/5.24-g23mdoc/sap/gen_bat.pl is missing from our PSL1DOC.tar.xz package
(again, see the main README file in this directory).  If you need this Perl
script, it is present in our FGW/LoCosto_hw_sw_docs.tar.xz package.