I used to be using an O2 Atom Exec phone. I’ve been wanting a GPS for a long time, and I discovered that it would only cost about twice the price of the GPS to buy a whole new phone (bringing it in from China). I also got myself speakerphone and hardware keypad facilities. Anyway, both phones use Windows Mobile 5, so I didn’t think there would be any problems with the software: Just sync my new phone to my computer and it should have all the contact and calendar information on it as the old one.

Well I encountered a *really* annoying problem. The new phone won’t display caller names for messages in the inbox. When I send to people, that is fine. When I receive messages from from people though, it only shows the phone number, not the name. When people call me, it does display the name. Huh?? It looks like with SMS, the international number is sent through (country code)(number). For a phone call, what appears on the screen is relative to the area the phone call comes from. So if someone in my country calls me while I’m in the same country, it doesn’t show the country code.

Now some specific examples. I’m in Australia. Country code is +61. If we have a number 0434 353 899, then the international version of that number is +61 434 353 899. Notice that the 0 disappears. The 0 is used when you are in the same country. What this means is that although we use 10 digits for a mobile phone number in Australia, only 9 of them are actual caller ID digits. You take the international representation of the number, remove the country code and count the remaining digits: 9.

Now back to WM5. There is a setting in the registry that tells Windows how many digits are used to represent the caller ID i.e. how many digits are used to represent the unique phone number. We know the answer is 9 for Australia (for mobiles). If we tell it to use 10, then it will constantly be looking to match 1 434 353 899 to our contact list, rather than 434 353 899. Now if I have 0434 353 899 in my contact list, it will match 434 353 899, and it will display the caller number. When someone calls me and the number comes through as 0434 353 899, it will still grab 9 digits starting from the right hand side, and it will still match.

How to modify the setting in Windows is not as simple as I would like it to be. Really, these are regional settings (vary from country to country with the phone number digits) and so should be user-configurable. What you actually need to do though is go into the registry and hack the value manually. So you’ll need yourself a registry editor. I used PHM RegEdit, which is a free registry editor for the Windows Mobile. You’ll also need ActiveSync, or some other way of transferring files to your Windows Mobile device (obviously).

Note that the registry editor comes with a lot of CAB files. My phone uses a TI OMAP processor, which uses the ARM instructions. If you have a MIPS based processor, obviously you’ll need one of those CABs. I originally installed the strgr version, which succeeded, but didn’t run properly. When you run the application, you should have plus signs (+) next to the 3 boxes that come up. It should look basically like it does on the PHM RegEdit download site. If it doesn’t, then you probably need to install one of the other CAB files. I tried all of the ARM ones until I found one that worked. It didn’t harm my machine by installing the others, in fact some did not install.

Once the registry editor is installed, you need to find the right key. If you expand the trees with the + sign to navigate to the following location:

Hkey_Current _User\ControlPanel\Phone\

And click on the CallIDMatch entry. You will then be able to edit the numerical value that it has there: Use the up and down arrows to increase or decrease it. Set it to the desired value. Click Ok.

Now reboot the phone. Messages that you receive from now will resolve correctly to the contact name. Note that messages that are already received will probably not be decoded: For me, the messages stored on my SIM were decoded to the persons name, but the phone messages were not.