Totally OT. Telephone numbers

[ARWadsworth]

Sorry for asking such an off topic question.

Does anyone have any idea why the last number that called my phone (I dialled 1471) has the phone number 00000000000.

Adam

[Rob Morley]

Engineer testing the line?

[Set Square]

Press 3 to call it, and see who answers!

[ARWadsworth]

I have not had fault on the line AFAIK. It is not the first time I have had unreturnable numbers call me. It is just such a strange number this time.

Adam

[David McNeish]

A switchboard set up with the "wrong" (or no) presenting number? On caller ID at work I quite often get numbers which are wrong (e.g. a digit missing).

David

[G&M]

Because the idiot who setup the PABX calling you didn't turn identification off and also didn't bother to program in the number it was using.

[:::Jerry::::]

identification

But surely the number given by a 1471 request is the number the calling exchange has given, that is why you have to tell BT to with hold your number and not an option on the phone IYSWIM ?

Could be that an BT exchange has baulked some place...

[G&M]

Large PABXs are themselves part of the switching network and run a special variant of the CCITT signalling protocol the exchanges themselves use. Thus they are inside the safety net and are expected to play by the rules without being checked. On these PABXs you can make all sorts of Caller ID options, though saying you come from somewhere else is somewhat naughty.

[Peter Parry]

Probably because it is an American call centre trying to sell you something really exciting like err... something really exciting. They seem to be the main culprits as the US telcos allow them to present numbers outside assigned ranges.

[:::Jerry::::]

I would have thought that the BT network would monitor given ID numbers against those from the true ID of the line being used for the call and at the very minimum return a 'caller ID with-held' default cal back ID IYSWIM ? Not to do so could, as you say, lead to the abuse of the system and open BT and the various watchdogs etc. to all sorts of problems.

If they don't do the above something is very lacking IMO.

[Peter]

When I was working in a voice design for a few months i learnt a little about CLI. It seems that there are 2 or three levels of CLI. One level is the actual calling number and cannot (read: "really, really should not") be altered / blocked / not passed. This level will be examined if there are any investigations etc...

There is also a "information" level, this is the level that 1471 and caller displays use. Subscribers can request that this is blocked or use the 141 prefix (I think this is the number).

Additionally where a company obtains its telephony from one of the many Other Licensed Operators they may choose to not present that level of CLI or present a different number. Often this would be the front reception desk for the building the call originated from or a central operator for the company.

UK OLO's are required to log details of all call that come through there networks, and keep these records indefinitely. (OLOs include BT, NTL, C&W, Global Crossing, Energis, O2, Orange etc...).

CLI is an international system, but of course some countries do not stick to the system, and there are ways of hacking the system. In particular phones companies in Las Vegas _have_ had a doggy reputation recently (mainly to do with diverting callers to alternative adult services etc.). Also there have been some concerns about the security of VOIP (voice over IP) and IPT (IP telephony), where it's been found quite easy to make calls and spoof the CLI.

00000000 was probably a call from a company "managing" it's own PABX. If it was a malicious call it probably could be traced.

If it was from outside the up it probably wouldn't have presented any number.

hth

-- peter

[Dave Liquorice]

Erm, what about outgoing only PABX lines, no point in presenting that number. So the owner of the PABX has the need to send a legitimate number for their front office or WHY.

[Richard]

Do NOT dial this number. It is the lockout code for the infinite improbability drive. If dialled it would freeze Arthur Dent and Marvin where they are about to be on Tuesday R4 . The Tertiary phase.

Richard.

[Richard Porter]

Normally international calls would just display as INTERNATIONAL. However recently I got a call from a freind from Belgium who was in the UK at the time, and his number was displayed complete with the international dialling code (0032).

I normally have ACR activated and I'm annoyed at the number of UK companies that make cold sales calls from overseas, and that includes Lloyds-TSB.

[Andy Hall]

I make and receive calls to and from most countries elsewhere in Europe and also the U.S.

At least half of incoming calls have the calling number presented - my (ISDN) PABX logs them.

It appears to be mainly dependent on originating carrier. For example numbers from most GSM operators appear, and from some countries, fixed line as well...

.andy

To email, substitute .nospam with .gl

[The Natural Philosopher]

Probably a PABX with an unset CLI.

[Terry]

"Bond. James Bond here"!