YES ! 

No.

141 tells the exchange you don't want it to display the CLIP to the far end - its upto the switches to obey the flag... There are a number of things you can do in order to get some or all of the CLIP from the calling party.

With special service numbers (087x 080x etc) part of your CLI may still be presented to the called party. Or at least an aera code, or the last 6 digits depending on the service.

With 999/112 101 (Type A service numbers) you can never hide your CLI. - Emergency services always get the full CLI of the calling party, also the billing address/name and if your a mobile we get location data from the network. If you call from a line thats only got 'soft' dial tone we still get records sent to us.

I'm not sure what we get if you call from a mobile with no SIM or an invalid SIM - we will still get location data, but I'm not sure what (if anything) else...

As an end user you can't really hide your CLI - only ask the telco to ask everyone else in the chain to not display it at the far end.

If you have VoIP, or an SS7 connection then you can do some fun things with CLI : )

Q wrote on May 28^th, 2009 at 9:38pm:

.... and (with the exception of "appropriate" persons) there is a legal obligation a) for the opportunity to make such a request to be provided, and b) for the request to be respected through the chain and complied with.

I am not sure if the same principle applies in any way to the cell location of a mobile call. Does anyone know the legal and regulatory position of this item of (is it "personal data")?

Q wrote on May 29^th, 2009 at 3:46pm:


If you don't want to say, then don't, no need for the stupid reply!

In reference to my above post.

These services are called "ANI READBACK" with hundreds of them, in hundreds of different area codes, any business connected to the SS#7 network via a TDM can view the CLI information regardless of the privacy flag.

Only BT is obliged to "honour" the privacy flag (141) and not display the Caller ID, any other call provider, Mobile, Cable, CPS, VoIP is under to obligation from any one to not delivery the CLI. B.T. Themselves state that no guarantee is offered when using the 141 service, people has just become accustomed to the incorrect belief that the Telecom Act 2003 or the Wireless & Telegraphy acts 1947 says that CLI is to be kept private.

Think about it, Caller ID wasn't even about when the Wireless & Telegraphy act was introduced. and none of the Telecommunication Acts (as amended in 1979, 1984, 1997, 2003, 2005) mentions any about Caller ID other than that it *SHOULD* be made available to the NOAS via the 999/112 system.

Never assume 141 will hide your identity when calling companies.  

Although most companies don't have the own SS#7 TDM connections, but those that do... well you've been warned.

sherbert wrote on Jun 14^th, 2009 at 1:44pm:


On your mobile telephone if you select "HIDE CALLER ID" or similar from the call menu, it will only prefix the call with #31# which is the GSM standards code to instruct the mobile switch that the CLI was requested to be withheld (ie add a privacy flag to the call like using 141). No one other than B.T. must honour that privacy flag.

Lets just be clear about this, no company has to protect the Caller ID, it is considered "best practise" not release the CLI. The company I work for receives CLI on all inbound calls regardless of the privacy flag. The staff who answer the phones are informed it is withheld CLI as the number is prefixed to indicate the privacy. The staff are told not to tell the caller the CLI is displayed as it causes problems, people complaining and such that 141 didn't work.

The easiest way to receive withheld CLI yourself is to rent a 0800 number from some company 0800 numbers nearly always provide full CLI, since your paying for the call you have a right to know who is calling you. The caller id may not be presented at the time of the call, but is usually supplied at a later date in call detail records.

sherbert wrote on Jun 14^th, 2009 at 2:06pm:


Sherbert, don't confuse yourself over it. I was just pointing out to DaveM (a global moderator) the he was in fact wrong, and therefore giving inaccurate information out to other members. - No disrespect intended to DaveM, but people would look to him as a global mod and assume his answers to be correct.

In simple terms.

Never assume that just because your using 141 or #31# your number is safe when calling companies. Even if you call from a corporate PBX that has multiple lines (usually ISDN PRI's) and the CLI is "UNAVAILABLE" which means it was not withheld, but no CLI was set. The main line CLI is sent as ANI as ANI is also used as the billing reference. To make matters even more confusing CLI and ANI are not the same system. ANI is often referred to as a "SUPER CLI" and that is what is sent to the NOAS on 999/112 calls.

Sherbert try this.... Withhold your CLI on your mobile, and call one of these 118 cowboy outfits, they'll still text the number to your phone, now how can that happen? - The only true way to ensure no one gets your number (other than those you permit to have it) is to a) not phone them;  b) use a payphone; c) a disposable PAYG SIM card.