More impossible Caller ID [Telecom]

"Adam H. Kerman" wrote

Because there is no one company or organization responsible for standards anymore (deregulation).......at least not one that actually DOES anything meaningful. And more importantly, there is no (financial) incentive to change anything.

Caller ID wasn't really a "mature" product when it was introduced so now we are pretty much stuck with something like a "Beta" version.

There's more places than the US, you know, and CLID works fine on international calls. If I call you, you'll get 12 digits of CLID, all real.

It is my impression that the rules against fake CLID are enforced better in other countries than in the US.

R's, John

so? I used to see more digits than that, regularly. International calls are all sorts of fun. :)

Because, _world-wide, telephone numbers are a variable length entity, and may be longer than 10 digits. The 'rules' for validating whether a given string of digits is a valid _international_ phone number get *really* messy.`

Some (many?) people design their devices to cope with more than just calls that originate in North America, and, thus may have more than 10 digits..

SS7 is designed for a broader market than just 'country code 1', and thus has provision for more than 10 digits in the CID info.

I *think* -- without digging up any references -- that the current ITU "specification" for a 'complete' telephone number (excluding any 'national' access code) is a maximum of *sixteen* digits.

and what do you do _if_ the 'checking' -- somewhere en route -- *DOES*" find an 'error' in the data? Abort the call? suppress the CID data? or pass what you have, and 'hope' the the recipient can make sense out of it. If you are the telco, how do _you_ decide which of those options your customer would prefer? What if different customers want different handling?

Lastly, CID is sent between the 1st and 2nd ring, as "Bell 212"-standard,

1200-baud, originate mode, signalling. If you remember the days of 1200 baud dial-up lines, you will know how sensitive to "noise that system was. It shouldn't surprise you, then, that under certain (common!!) conditions the CID signal from the C.O.

An extension? An internal billing code?

The country code wouldn't be part of the caller ID, although it could be added along the way, I suppose.

They don't allow the subscriber to set it himself?

A phone number, starting with country code 44.

That can't be it -- there are plenty of DID PBXes in Europe where the only way the telco switch knows the calling number is to get it from the PBX. Earlier this summer I was at a hotel in Germany where the main number was something like 2345-0 and you could direct dial room

678 as 2345-678. I called my mobile phone and the room's direct number showed up as CLID.

It is my impression that CO switches know the range of numbers assigned to a connected PBX, and are supposed to be programmed so that if CLID comes in outside that range, it substitutes the main number. But American telcos are sloppy and don't bother.

R's, John

ITU-T Recommendation E.164.6.2.1 still says 15 digits; I looked it up. That includes a country code length of 1-3 digits and a national (significant) number of 15 less the length of the country code. The national (significant) number is the national destination code and subscriber number.

btw, the list of country codes is not published on line by ITU-T. I suppose it's in one of their documents for sale.

I don't know what 6.2.4 refers to, the specification for "groups of countries". It does NOT refer to NANP as the country code specification is fixed at three digits, so I assume the purpose is to allow a set of European countries to adopt their own international numbering plan.

Sure it is. See

It appears to be an overlay for services that want to be reachable in several European countries. See

R's, John

While we're on the subject of caller ID.

The number of spam phone calls I'm receiving with caller ID information blocked is epidemic. I honestly think it's worse today than it was before the Do Not Call list. For several days the phone would ring at exactly 8:00 AM with the CID information blocked. I answered it one morning, said "Hello" and waited for 15 to 20 seconds and no one came on the line. The next morning I answered it and after about the same amount of time I voice came on asking for "Tina". There is no "Tina" in my family. Instead I asked him if he was aware it's illegal to block caller ID information. He said, "This is a personal call, not a business call" which I thought was an odd response if it were truly a personal call. At that moment a "beep... beep... beep" came on which I believe indicates the call is being recorded or monitored. I asked him directly the name of the company he was with. He refused to answer. After my third or fourth query he told me who he was with. I personally have a policy not to disclose company names on this forum, so I won't. I'll just say he was calling on behalf of a national discount warehouse club. I informed him there's no one in my house named Tina, my number was to be removed from his call list, and I would file a complaint with the FCC. While on the phone with him I dug this up.

I immediately pulled up the business in question's website and complained to them. I cited the above webpage and I let them know I would report them, which I did.

Yesterday I received an email from said business thanking me for signing up for their email newsletters. It doesn't sound like my complaint was taken all that seriously. Given the sheer volume of telemarketing calls I get, many of which block their caller ID information, it doesn't surprise me they aren't deterred. I don't think the Do Not Call list is working.

John

Good point about CLID. Most people don't realize that the CLID we use now dates back to the early 70's. I recall a book I read that indicated CLID was developed in 1972.

We need a version of rdns for phones.