Can't trace Blocked CID?

Bomb threat at a high school "could not be traced by caller ID because it was a 'blocked' number."

I know inbound "800" numbers get ANI even on "Blocked Caller ID"

I could have sworn that there was a field called something like Responsible Billed Party that appeared in our DEX records. That contained the dialing number, and we turned it over to the police in the case of harassment of one of our employees, but the police said they couldn't use it without a search warrant. That was on a call forwarded to a voicemail, but I thought it was present on all of the calls. Maybe it was only on forwarded calls.

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- - Clarence A Dold - Santa Rosa, CA, USA GPS: 38.47,-122.65

***** Moderator's Note *****

SS7 packets always contain the calling party ID, but the *DISPLAY* of that number is blocked at the terminating office if the "do not display" bit is set.

The person who received the call probably wasn't able to hit the code to report the calling number, since that capability is missing from most PBX extensions. However, the police can ask the LEC to search its billing records to find out which number the call was placed from - those are the "Local Usage Detail" records, which police refer to as "LUDs".

Most LECs keep usage records of all calls, for use in trunk planning, growth forecasts, sales campaigns, etc. However, the originating switch might not be capable of doing that, or may not have been programmed to keep such records.

Bill Horne Moderator

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It is possible the recipient wasn't aware of the Call Trace feature (*57). The phone company does not advertise it. If someone does use it, it charges a premium ($5) to use it and isn't very consumer friendly to users. So, it's likely most people aren't aware of it. Also, it seems most people don't know that caller-ID can be spoofed and the number displayed may be false.

In my humble opinion, Call Trace (which I believe goes for ANI and other 'hard data') should be advertised and its usage encourage for _any_ illegal phone call, including sales marketing. In my area, the telco discloses nothing to the consumer, and only reports it to the police. If one receives, say, an obscene phone call at 3 a.m., nothing is done until there is a repeated pattern of such calls.

I can't help but get the feeling the telco doesn't wanted to be bothered with such stuff. Likewise, I think the police are only interested if it is a true life & death threat, not, say, harassment from a ex-partner or illegal sales pitches.

***** Moderator's Note *****

Even if a PBX user knows how to use Star-57, he is usually unable to employ it, since in order to do that, he'd have to be able to dial an outoging call on the *same* *trunk* that the call came in on, *before* the trunk was used again.

Bill Horne Moderator

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That's what I recall. I was surprised to see that field populated after all the "couldn't trace" comments I've seen in the news, and our own experience with lack of followup back at the time I was at that telco.

The only thing I could surmise was that it was a field that was dropped when records were saved to longer term storage, unless it was needed for billing that call.

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