NGMsGhost wrote on Apr 13
th, 2010 at 8:49pm:
Dave wrote on Apr 13
th, 2010 at 7:49pm:
How do you suppose TPS and ICO could investigate with no information to go on?
By insisting that the telephone company of the person called disclose the CLI of the calling party as part of their investigation in to these illegal calls to TPS registered lines. Supposedly my telephone company should disclose the CLI to me if I maintain the caller was committing a crime when they called but they have always refused to do so. Usually there is a CLI still available, even when the call is from overseas. Although as we have seen some of those overseas call centres quite deliberately fake nonexistent UK number ranges such as 06.
I am not so sure that this would actually provide any real benefit, particularly as it may simply give rise to more spoofed and unavailable CLIs.
A quick explanation of CLIs will help readers understand my points:
CLI is "Calling Line Identification" and it is system that allows a number to be presented on caller displays and read out via 1471. Hence, a number on caller display is often referred to as "a CLI number" or just "a CLI".
Calling Line Identification means the identification (telephone number) of the calling line (the telephone line that the caller is ringing from).
The calling and receiving parties of any individual call may be with different telephone providers. Let's refer to the caller's telephone company as Provider A and the recipient's provider as Provider B. During a call, Provider A passes the CLI number (along with the call itself) to Provider B for display on its customer's caller display unit.
Where Provider A and Provider B don't interconnect with one another, then they will use another telephone company, Provider X, to transit the call between them. In which case, the call will go from Provider A to Provider X to Provider B, with a CLI being passed on at each interconnection.
Any request that the caller makes to withhold their number from the recipient (by prefixing the number with 141 etc) is fulfilled by Provider B. So Provider A gets the request (from its customer) to withhold the CLI. It passes on the CLI number and the withhold request to Provider X (iff applicable) and it in-turn passes it on to Provider B. It is up to Provider B to honour the request and keep the CLI from its customer (the receiving party of the call).
NGMsGhost, what you are suggesting is that the recipient's telephone company, Provider B, should be compelled to provide the CLI when its customer says that a call breached TPS or committed some other offence.
I think that any such legislation would be a waste of time due to the total lack of ruggedness in the reliability of the CLI system. When a caller receives a call, the CLI presented to them (assuming that it has not been withheld) cannot be guaranteed to be accurate by their telephone provider. All the recipient's telco (Provider B) can do is present the CLI number that it is given by the telco passing the call to it. [By "accurate", I mean that the number presented is one which the caller can be reached on.]
I would have thought that any party out for malicious intent would wish to provide a fake CLI rather than simply request the recipient's provider to withhold it (a genuine one) from its customer. However, for the purpose of this discussion, I will assume that some do provide genuine CLIs, but withhold them.
Should there be an onus put on receivers' telcos to disclose CLI numbers of those alleged to be breaking rules, then all this is likely to achieve is that those doing the rule breaking will have their telco present a fake CLI. Indeed, the prevalence of subscription to services that reject calls where a numbers are withheld means that they are probably more likely to provide fake CLIs rather than withhelds. Such examples of fake CLIs known to be used are a line of 0s and "1111". How do you propose TPS and ICO trace these? What happens if scammers catch on and start to share the same fake CLI?
Indeed, this thread is about a scam using a fake CLI. So withholding the CLI has nothing to do with it!
If you look at all the e-mail spam that is about, the same problem exists there. E-mails are sent from fake 'from' addresses and even the sender's IP address being recorded in the header does not abate the tirade. And so, CLIs are like 'from' addresses on e-mails; they can't be trusted to be genuine.