Background A program to graphically interface the Home Location Register (HLR) of GSM service provider Indigo-Somoncom was developed using Visual C++ .NET 2003. The purpose of the work was to create an easy-to-use interface where subscriber entries and statistics from the HLR can be presented. Furthermore, lists of subscribers belonging to any of the following categories where requested by the Billing Department of Somoncom. Subscribers with international roaming enabled. Subscribers with the OCE-service enabled. Subscribers appearing in the HLR but not in the AUC. Solution The only way of direct access to the HLR is through a RS-232 text-based terminal where commands can be entered to view or alter the subscriber records. By giving the Display Subscriber command at the terminal, followed by the Subscriber Number (SN), one entry at a time can be printed to a log file. Unfortunately there is no command for printing all subscriber entries at one time, but a List Subscribers command to generate a list of all SNs in the register is available. This list was processed to generate a big text file with Display Subscriber commands for all subscribers, simply a list of all commands that would have to be given at the terminal to print out all subscriber entries. The terminal has support for Visual Basic-script, so a short routine in this language was used to automatically enter all these commands. The next step of the program is to process the generated HLR file. A number of functions were developed to get this done by going through the HLR file line by line and search for the vital records of every HLR entry. A binary data file is used to make the data more manageable, since the HLR file is of a very big size. Statistics are gathered upon processing the HLR file and saved to a statistics data file. A Graphical User Interface was created that contains an HLR browser where the user can view one subscriber at a time, stepping through the database with the navigation buttons as well as searching for a specific SN number. It also contains a section to view and compare statistics gathered from different HLR text files. The subscriber lists requested by the Billing Department is also presented here, as well as in a text file. Conclusion The program performs what was requested, but the major drawback is the time it takes to create the HLR text file. One important aspect not supported by the program is the fact that one subscriber may have several SN numbers; the program only stores one SN number from each subscriber.