Bens_Mum wrote on Oct 14^th, 2008 at 3:59pm:


That's a bit defeatist. You don't need to spend very long, just two or three numbers may reveal the algorithm. Post any numbers you've found here if you don't want to figure it out yourself. Any students with brains and who care about saving money will be delighted to know the geographical number for their room, so shouldn't be irritated when you call. (If that last sentence sounded ironic, it was intentional!)

Dave: it should be just as feasible for any of us to try some numbers. If you have inclusive calls, do you fancy a go?

It is true that the Porter wouldn't be able to give out the extension for your son. However, you could get your son to ask the Porter what extension his phone is - that wouldn't be violating the DPA.

Bens_Mum wrote on Oct 17^th, 2008 at 2:10pm:


Who told you that? The university? We already know that's the official line, but you said you had got through to some rooms with geographical numbers.

Bens_Mum wrote on Oct 17^th, 2008 at 2:10pm:


Was the number you tried 01524 51xxxx, which you said seemed to get through? There may be an offset or the first number might be different. Can you remember what number you dialled when you got through to a room?

For example, if your son's external extension is 1234 and his internal number is 3789, that might indicate that external numbers are in the range 1000-1999 and internal ones 3000-3999. You therefore may have called the person with internal number 3234. Therefore try 01524 51 1789 to reach your son!

Remember, if it's the wrong room, tell the student what his or her geographical number is, and try to find out their extension!

I believe that of those university systems which have been cracked, that the last two digits of geographical, 0844/0870 and extension match.

Perhaps you could send me a private message with your son's extension number, 0870 number and the number you tried which you think was a student room and I can suggest which numbers to try so I don't have to explain what I mean generically (ie without knowing the exact number).

Refer back to your post in reply #38 in this thread where you said that it was 01524 51 which got the response you thought might be a student's room.

jrawle wrote on Oct 17^th, 2008 at 9:19pm:

Indeed. Which means that if you have found one of the numbers within the block of numbers for the student accommodation, then "homing in" on the correct one for your son is likely to be a case of trying 10 or 20 possibilities at most as it's likely that the last two digits will be the same, thus the numbers will be offset by a multiple of so many hundred.

If you PM me with the numbers, I will explain what I mean.

seesma wrote on Dec 1^st, 2008 at 8:26pm:

The previous poster seemed to give up. If you can try some numbers, that would be great!

Perhaps we can start from nearer the beginning again. Your son has a phone number in the form 0844 xxx xxxx? Does he also have an internal number in the form 5xxxx? Any information you can post here will be helpful (you probably should xx out the last two digits of any numbers you post).

The previous poster had some success with the number 01524 51xxxx, but it was a different student's room. We need to find out a few pairs of numbers so as to crack the algorithm.

seesma wrote on Dec 2^nd, 2008 at 7:27pm:

That might help us to work out how internal and 0844 numbers are related, but we don't really need to do that if the students already know these numbers.

What we need to do is work out how these numbers relate to a third set of numbers, which are probably in the form 01524 51xxxx. The xxxx could be related to the internal extension, or to the 0844 number, possibly offset by a certain amount.

The only way to find this out now is to try some 01524 numbers. You can start by using the last four digits of your son's internal extension in place of the xxxx.

If at any stage you get through to a student, you need to ask them nicely to give you their internal and 0844 numbers. Explain that you were trying to call your son (maybe they know him!) and that you are trying to use a different number that's free to dial from mobile phones - even if you are using a landline, that's a good way to put it to students, who may already be realising that calling their mates in their rooms from their mobile is costing a fortune. If the student you have found at random tells you his or her numbers, you can give the 01524 number in return - fair deal! Oh, do call at a time that's considered sociable by students - if you call at 9am, they aren't likely to be too eager and willing to help!

Make sure you note down anything you find out. And don't forget to note the number you have dialled too in case you forget what you tried! Note down any failures too!

If you find a working number and its equivalent, you may see a pattern that allows you to work out your son's number. For example, if 01524 516789 goes to internal extension 54789, the last three digits need to stay the same, and 2000 possibly be added to the number.

Please let us know any pairs you find out. If you are worried about posting students' phone numbers here, you can send it in a Personal Message (PM) to me and other regular forum members such as Dave so we can have a look. (Having said that, we don't need to know the students' names along with the numbers, and if anyone wants to phone random students in their rooms they can do that already!)