simparser.pl is a tool that can decode SIM traffic created by the HTerm
application. Once HTerm has received some traffic, press the arrow button
next to "Save output", and set the storage format to "Hex". Enable the
Timestamps tick box. Now, save the .log file to the same directory as
simparser.pl.

Then, open the file in a text editor and add a header with no empty lines,
ending in a single empty line. (If you don't want to add a header, prepend the
actual data with a single empty line.) For example, the top of the file may now
look like this:

  Date: 13 december 2011
  With: RebelSIM, HTerm
  ME: Nokia 3310 (1)
  Baud rate: 8431

  17:13:02.197:
  00FF
  17:13:02.197:
  00
  [..]

Then, run:

  simparser.pl <filename>

For example:
  simparser.pl output_2011-12-13_17-15-06.log

The simparser will first write your header to standard out, followed by a
parsing of the protocol.

Written by Sjors Gielen <s.gielen@student.ru.nl> in 2011-2012 for the "SIM
Toolkit In Practice" bachelor thesis.