mptc -- Mobile Phone Tariff Calculator

Introduction

I knocked up this program to figure out if I could save money on mobile (cell) phone bills. Turns out I could -- about 15 UK pounds every month ... quite handy for a poor student!

To use it, you feed it a copy of one of your itemised phone bills as a plain text file in a very simple format, together with a tariff file for the tariff you're currently being charged on, and a tariff file for each tariff which you're considering switching to. (A tariff file is another plain text file, again in a very simple format, describing all the characteristics of a tariff, such as cost per minute for different categories of call, how much you get in free calls each month, cost of sending SMS messages, which times of the week are considered peak or off-peak etc.) It will then recalculate your entire bill for each of the tariffs you're considering switching to, so you can see whether you would have saved money by being on that tariff instead.

Features

Fairly complete understanding of the monthly line rental systems of the four major UK mobile phone networks.
Call classification categories include distinction for calls to local/national land lines, calls/SMS messages to mobiles on same/other network, operator calls, and free calls. Classifies calls using pseudo-code defined in the configuration file. Also looks at the call cost and compares it with the known rates for various call categories to determine whether a call is cross-network or not (calls to mobiles), and whether a call is local or national (calls to land lines).
User-defined pricing bands (e.g. 7am to 7pm weekdays classed as `daytime', other times during the week classed as `evening', and weekend classed as (gasp) `weekend'.
Support for initial network connection and monthly line rental fees.
Support for a certain number of minutes of free calls per month for certain calls categories.
Understands VAT (UK tax).
Optional minimum call length feature.
Prints details of each individual call, and detailed totals for all the various call categories over the whole bill (both optional).
Can sort calls by category or by time, or both.

Limitations

As I wrote it mainly for me, it's currently geared towards UK mobile phone network tariffs with monthly line rentals. It does not support the `pay as you go' or `pay for a whole year in one go' schemes, but those schemes tend rip you off anyway unless you're hardly making any calls, in which case you don't need this program anyway.

It served the purpose I wrote it for (to advise me which network and tariff to switch to), and because I have a lot of other things to do, taking the time to make it useful for other people has taken a back seat. Hence although the software seems to work fine for me, it should be considered as alpha software. It is full of rough edges, so unless you have a small amount of expertise in computer languages in general, there is no guarantee you'll find it useful. There's no guarantee even if you're Larry Wall, but you know what I mean.

However, there should be enough functionality in there that given someone with sufficient Perl skills and interest, it could easily be adapted to be suited for use in other countries, and maybe even turned into a polished product. I haven't the time or motivation to do this myself, so I'm hoping that other people will chip in.

How do I use it?

Unfortunately I don't have time to produce full documentation, so here's a brief introduction:

Download and unpack the tar ball or the zip file containing all the bits and pieces.
Look at the tariff files, and if the ones you need aren't there, use the ones there as examples of how to create your own. It should be pretty obvious how they work.
Look at two of my bill files which I included in the distribution as samples. Each line is in one of four formats:
1. A blank line or one which begins with `#' is ignored.
2. A line which looks like 7/1999 means that the following lines contain information about phone calls in August 1999.
3. A line which contains a single number means that the following lines contain information about phone calls on the date corresponding to that number in the current (as defined by the previous line format) month.
4. A line with four entries in it (separated by whitespace) denotes that an actual call was made. The four entries are:
  1. the time of the call in HHMM format,
  2. the number called, or at least, enough of the prefix to be able to figure out what type of call it is,
  3. the call duration in MM:SS format (the MM and even the : can be omitted if desired), or
  4. the cost of the call, or `b' if this call was free as the result of being part of a "bundle" (free monthly calls). Append `pb' to the cost if the call was only part bundle, i.e. if it used up the last remaining bit of the bundle, so that part of the call was free and part was charged.
Write your own bill file, or better yet, persuade your current network service to make your bills available as computer files. Let me know if you succeed at the latter.
Look at the configuration file mptc.conf and edit it as necessary.
Install Date::Calc from CPAN if you haven't already got it.
Run the program with no parameters, and it will tell you what parameters to provide.

I want to help!

Great! Read through the source and get hacking. Here are some of the things you could do:

Write some documentation! Boring, but very helpful.
Redo the configuration file and tariff files for other countries.
Write a nice front-end to alleviate the hassle of entering phone bills by hand. A CGI-based front-end would be particularly nice.
Add support for pricing systems in other countries. If you're successfully using the program outside the UK, then fantastic, let me know!
See the to do list for other ideas.

It should be fairly clear how everything works, but if something puzzles you, ask me about it and I'll do what I can to help. If you've made some changes to the code, please send them to me in unified diff format for inclusion in the next release.