A number of mainstream carriers and call providers as well as NGN suppliers are using the DNIS service to prevent people dialing the geographical number direct.

DNIS in short is-

Dialed Number Identification Service

Basically, when you dial a number, the carrier receives the number you've called, and can route those calls differently, an example of this is

A call to ABC-Bank on 08701234567 diverts to the geographical number of 01131234567, of course dialing the 01 number is going to be cheaper, but those companies who are implementing the DNIS will receive the dialed number in whats called the ANI part of the call, thus will allow the company to see which number was dialed and treat those calls differently to those calling the NGN.

So calling the 0870 will enter your call into the call queue but dialing the geographical number will result in the call handled in which ever way the company wishes, even enabling them to announce number out of service or some other recorded announcement.

I'm a telecoms engineer for a large carrier and we have been provisioning the DNIS for a number of commercial house-hold name businesses, although it is my job (and of course my source of income) so I sadly can't disclose the businesses which have implemented this service, with this, a number of the geographical numbers may cease to connect even though it is effectively still the correct number where the termination is configured to.

I still 100% support that of SNT0870 and use it myself!

SilentCallsVictim,

Some of the businesses which have so far requested implementation and have the service available to them now, generate that much revenue on NGN's the companies are prepared to do what it can to protect the extra income it receives.

These businesses are from a mass of household names, from financial institutions and utility companies to entertainment.

Of course i'm all for businesses using technology for the better, but not to fleece the customer as it is those very customers who are keeping them in business.

irrelevant,

I here what your saying, but it sounds more like "Reverse Call ID" is what you used, as DNIS is part of SS7 signalling, and alot of businesses these days also have the own SS7 switching equipment, and so long as they've signed an agreement with the inbound carrier, calls with a privacy flag (withheld/141) CLI is still received in full allowing the business to view withheld CLI, just the same as calling BT or T-Mobile for example, these companies will still receive your CLI regardless if it is withheld, it is allowed too as businesses use it to obtain the geographical information of where it is receiving calls from.

An example of this is utility companies use this information to record trends, such as LocalElectric starts to receive a high number of calls from people connected to the 0131560 exchange, it can indicate a power outage or other fault, so before even answering any calls it could be safe to assume of a problem in that area.

Don't take the CLI out of proportion, only the companies with the own SS7 switching equipment are able to do this, and it isn't your everyday company, although most call centres if not all have this equipment to handle the trunk lines coming in from the carrier.

Another thing, withholding CLI is and never was designed to be totally private, as each carrier needs to pass the CLI and ANI data onto each other during the call setup leg.

This has and always will be the case, as that information is required on the receiving swtich to be able to route the call and log in the CDR correctly, the sending switch simply tags the CLI with a privacy flag which the receiving switch on the interconnect is to ethically honour the flag and not reveal the CLI to the end user, a user with the own SS7 switching equipment will also receive the CLI with the privacy flag enabled.

Once upon a time when calling to a number of international destinations even with 141 prefix the CLI was still been displayed, as the UK's CLI is PRI-ETSI(UK) basically none standard, and some international switches didn't understand the privacy flag. This problem only effected calls originating via BT Switches, Cable and other Teleco switches didn't do this, BT however now do not process any CLI on international inbound/outbound calls, except operator connect calls.

SilentCallsVictim wrote on Oct 15^th, 2008 at 12:00am:


Also in that act, in section 14, is a prohibition of processing of the location of the caller, unless they have specifically given their permission beforehand.  This seems to imply that the uses Hobbie is suggesting are already being made of the numbers is also in breach of the rules.

irrelevant wrote on Oct 15^th, 2008 at 6:27am:


Not quite. 14.2 is broken into two parts.

In part (a) There is no prohibition "where the user or subscriber cannot be identified from such data".

It is therefore perfectly acceptable for a call to be directed to a call centre covering the general geographic area from where the call was made, or for the general location of the caller to be made available to the person receiving the call.

When you phone your partner to say that you have been kept late at work, you can conceal the precise place you are calling from, but not the general location. Choose a pub very close to the office.

Part (b) requires consent where a value added service is to be provided.

It must be noted that regulation 14 (like 10) covers the activities of Telcos. In the case of mobiles, it covers the cell from which the call was made.


We are however drifting off-topic, as we are supposed to be discussing DNIS. I cannot see any privacy implications with this. The dialled number is clearly information that one is happy to provide, having chosen to dial it.

Hobbie wrote on Oct 15^th, 2008 at 2:38pm:

Thank you.

This is very useful information in the context of the database. It would also be useful if alternatives to which this is applied could be flagged or deleted.

Saynoto0870 is however not just a database. It is a campaign against the improper use of revenue sharing numbers. This may be because the context is inappropriate (e.g. for public services or complaint lines) or because the cost of calling is not properly advised. Some would say that there is no proper use of revenue sharing numbers.

Use of unpublished alternatives is just one way of undermining improper use. The purpose is to get propriety re-established.

Those who have a valid need for a non-geographic number now have 03xx as an option that denies revenue share and gives an assurance of no call rate surcharge.

There are many situations where unpublished alternative numbers are not found or are unsuitable, e.g due to use of DNIS. This is no defeat for SNT0870, the campaign must go on.

It seems to me that this is something only a small number of companies will do: large companies with a certain sort of telephone equipment. It also seems that it may be possible to cirumvent by using certain dial through operators because of the way their calls are routed, or maybe using certain VoIP services.

Any company who tells people calling them on a particular number that they shouldn't do so - whether through a system like this, or through an Aliance & Leicester-style interrogation - is simply revealing their true motive for implementing revenue-sharing numbers: to make extra profit. The best solution for saying NO to 0870 numbers in this case is to take your business elsewhere. If that's what our campaign needs to concentrate on, so be it.