Caller Line Identification (CLI) is a method introduced by BT to the UK a couple of years ago. Initially with the idea that it could give you more detail about who called you or even when you were being called the ability to see who was ringing was possible. Many other phone companies took up the system and the subscribers had the option to use it or hide their number with CLI Barring when they were calling somebody else.

As the age of the Internet grew and all of a sudden 0800 access systems started to spring up we saw a new wave of CLI. This time with far from a friendly purpose and ultimately used in a way that could cost you and many other Internet users a lot of money!

Has your ISP been CLI infected?

CLI was initially brought in for 0800 ISPs as the first real way of stopping illegal accesses by unauthorised users to systems and accounts. It meant that even if you had the right security details, if you weren't dialling from the right line then you would be unable to connect. Other ISPs like BT Internet were simply using it to monitor who was using what account and from where rather than physical barring. Certainly a very clever system and one that was being used correctly, or so we thought.

Within about a month CLI was being used by nearly 30 ISPs and only 6 of those offered any kind of 0800. The problem came when mobile users who are constantly travelling or have no real home found themselves in trouble. They were being called warning them of illegal accesses to their accounts or not even being able to get through to their ISP at all.

BT Internet for example, while they allow you to login from another number they will also phone you and warning you of a security breach with your account. This is because they saw access to your details but from a different number and when you try to explain they would threaten to close your account. A look into their Terms of Service suggests this is in-appropriate behaviour (on their part) but when we tried to contact BT (even as customers) we would not be spoken to.

It gets worse?

So image this, not only would you have to sign up for a new account for every different number you used but you also couldn't sign up for extra accounts in the same location. Try signing up for two accounts for different family members (in order to stick directly to the rules) under ClaraNet on the same number, it's impossible because they only allow one account per specific CLI and it's a fault of the system not them (or so we are told).

In essence it's an impossibly vicious circle. You can't have more than one account on the same number with an ISP that is overly restrictive when it comes to CLI and you use the system from another number without another account. Instantly any Laptop users or those that travel are unfairly penalised. Business accounts are unlikely to support CLI thankfully but then the problem is they are unlikely to offer free or discounted call systems as well so there is no way to win.

In the end you have to pay large sums of money just to access the same provider from a different location. Such a system is unfair on the end user and while it stops security risks, at the same time limits the freedom of any one registrant. So be warned, if you're a traveller then ISPs such as ClaraNet, BT Internet and whole host of others may not be for you.