Arrrg OFCOM, again

OK, there is a rule (general condition 4) that says we have to make location data available to emergency services for 999 calls (and 112).

My reading of it is pretty simple in that (a) there is no location data in the signalling system, so nothing to send, and (b) we only have to make available which could be a web site if we wanted - nothing requires us to even "agree technical standards".

OFCOMs view is very different, though they fail to explain why in any sensible detail. They consider we have to update BT's database for emergency calls (based on CLI). Well, we could use C&W database and routing instead, they say. But still, we are expected to send (not "make available") the data in a specific way to a specific system.

Lets try and meet that new and unwritten requirement shall we?

Catch is that for a load of the numbers we have we can't do that. The issue is we have two carriers and number hosters and a load of numbers actually from one of the carriers. We only use one carrier for 999 calls. We can only update the numbers we have hosted with them on to BT's database (for now). So a whole load of number we cannot yet update. We have around 4 million numbers we can and a few thousand we cannot.

There is a long term plan (which could be months to sort this) allowing us to update for any of our numbers via the one carrier. However OFCOM are bullying. No amount of "we do actually comply anyway so stop bullying" is working.

So I had a cunning plan. A simple plan. It is a sort of NAT for phone numbers (someone on irc suggested it was Customer user Number Translation or CNT for short). But basically any numbers I cannot update gets an 0200 number allocated and that is updated in the BT database. Calls to 999 present the 0200 number, and they get the location data. (0200 is a special code for hidden numbers in the network, so ideal for this).

Job done - compliant - all end users calling 999 can have location data (if they set it).

Is that good enough for OFCOM?

No, of course not. But I cannot see how it is not compliant. They seem happy with it as a temporary solution. It makes no sense - either it is compliant or it is not. There is no "temporary" to it!

We will have to see what they say.


  1. Isn't 020 0 actually a London number (like AAISP's 020 00 20 range?)

  2. CNT sounds like a kludge.

    Can't you use Specific Home Indication Technology?

  3. Yet you still won't know for sure where the person making the call actually is.

    I for instance send my calls to an offsite PBX before sending on to you, so tracking it back via IP probably won't be much help

    Whilst most of the time I do tend to use my Voip line from home, I do sometimes login elsewhere such as on a soft-phone from my laptop over a VPN so even sending the billing address isn't necessarily right.

    I fear that Ofcom fail to understand how Voip works.

  4. Doesn't the number presented have to be routable back to the caller so if, for example, the ambulanceman needs to call it s/he can.

  5. Nicholas, that is an interesting question.

    1. The 0200 is a number they can call back though.
    2. People can have outgoing lines
    3. People can have anonymous call rejection

    So regs have to allow for a number that cannot be called back.

    In fact, I cannot see any regs saying the number has to be "right" or something that can be called back. Even so a lack of actual rules or law will not stop OFCOM being a pain I am sure.

  6. compliance with vague rules aside, I wonder if the 020 an awkward (at the point of life-threatening crisis) user interface problem: 999 operator performs some number read-back/passes it on to someone else, and original called is WTF ARE YOU TALKING ABOUT SEND ME AN AMBULANCE WHERE DID YOU GET THAT RANDOM NUMBER FROM?

  7. Oh, yes, that was in fact one of my concerns.

    I have in fact made the page where you put the location details on our control pages say "For emergency services calls your number will appear as 0200XXXXXX" so that people are aware this will happen.

    I am thinking of making the system send an email once the address details are confirmed, detailing the number, and the internal 0200 number that shows and the address details that have been confirmed. I think this would be a helpful touch.

    This is however one reason I am hoping to get some neater solutions that avoid this in due course. We'll get it sorted as fast as it is practical to do. But I refuse to be bullied in to something that is not a legal requirement.

    The regulations don't in fact require a user to even have a phone number.

  8. I have done that - we now email details once confirmed in the BT database including the fact that an 0200 number is used and what it is.

  9. SimonF: Mixing up Customer user Number Translation with Specific Home Indication Technology is surely not to be recommended lightly?

  10. Timmy.Norris said...
    "Having a VPN will definitely solve your problem."

    Can't see how it helps

  11. The routing can be customized. There are different ways you can adjust depending on the carrier.

    call recording


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