Techy odds and ends

This is an area where there's a huge amount of confusion. With any luck this article will clear a certain amount of it up. Broadly speaking, there are two types of each model of phone. It's actually far more complicated than that with regional variants, promotional offers etc., but let's keep it simple for the moment. On the one hand, you have the phone as it was originally designed by Nokia and containing Nokia's firmware. On the other hand you have phones that are distributed not directly by Nokia or their retailers but by mobile network operators. In the latter case, the firmware installed in these phones is modified by the network operator to include their logo, links to their services and a few custom features and settings. Occasionally, network operators will also deactivate features of the original phone that they don't want you using. AT&T come straight to mind with their paid-for voice dialling service − the phone already has such a feature built in but...

Clearly, there's alot of confusion out there as to what all these codes do, what they protect, how to get them and how to manage them. I'd like to clear that confusion up a litle bit with this article. The first thing you have to bear in mind is that your SIM card is actually the property of your network operator. SIM stands for "Subscriber Information Module". Stored in it is information that identifies you as the user of the phone in which the SIM is installed, and which ties that phone to your mobile phone number. Proof of this is if you swap SIMs with another phone and call your number it's the other phone that will ring, and if you place a call with your phone it's the other phone's owner who will be billed! The PIN, or "Personal Identification Number" is a 4-digit code (well, actually, some phones allow up to 8 digits but it is nearly always 4 digits), stored in encrypted form in the SIM and which protects your SIM from unauthorised use. Th...