Talk:Automatic number identification

{{WikiProject Telecommunications|class=start|importance=}}

Block

If anyone has a verifiable source that indicates whether the type of caller anonymity generally provided to certain civil servants such as district attorneys and public defenders is just caller-id blocking, or whether it prevents ANI identification as well, please add it to the article. --Elvey 23:37, 21 February 2007 (UTC)

I called one of the credit reporting agencies toll-free numbers from such a line and they were able to tell I was calling from California. So these lines just have Caller-ID blocking. --69.12.142.18 23:57, 28 February 2007 (UTC)

ANAC disagreement

I support the includer on this one. Early in my career when I was wiring the OSL in 5XB Switch for Automatic number announcement circuit, it was MFANI. Nowadays of course it's different but let's have a little ancient history. Jim.henderson (talk) 02:21, 1 April 2008 (UTC)

Point taken (on ANA) but I think the diatribe into secrecy, payphones, and criminal activity is a bit much. Bellhead (talk) 21:01, 6 April 2008 (UTC)

Isn't CPN the thing now?

I thought it was all about the CPN number. ANI seems rather old and depreciated. The number you see on your callerid display is derived from the CPN field. When somebody "blocks the callerid", usually by pressing *67, the originating carrier sets or appends the "Private" flag onto the CPN field. However the phone number is still sent. It is up to the receiving carrier to honor the Private flag and not display the number to the subscriber's callerid display. Even today the computer systems that control tollfree numbers just receive the CPN data directly, and often just ignore the Private flag. It seems the description of the earlier ANI system simply didn't have provisions for Privacy blocking, whereas appending the Private flag in the CPN will not do anything with a tollfree number as the computer system just ignores it. 66.114.93.6 (talk) 06:35, 2 October 2009 (UTC)

ANI is not depreciated. Don't confuse it with CallerID.

ANI was not intended to provide privacy. In fact, it did just the opposite. The philosophy is that if you call a toll free number, you are not paying for the call and have no right of privacy. The subscriber to the toll free number is going to get billed for the call and the bill needs to include an identifier for each call. The billing telephone number (your BTN field below) of the calling party is used for this identifier. For most individuals the billing telephone number is the calling party number. However, if for example you have a second line put into your home, most likely you will have it associated with your first number so that you only receive one bill. In this case, a call from your second number to a toll free number would cause your first number to be delivered as the ANI information. But a call from your second number to your friend would deliver your second number as the callerid information.

ANI delivers billing telephone number. Callerid delivers calling party number. At least that's the way its suppose to work. So technically, a toll free number is not ignoring the private flag of the calling party number, its receiving the billing telephone number as designed. Bellhead (talk) 20:02, 7 October 2009 (UTC)

Callerid Spoofing is simply spoofing the CPN. When you set the number in your PBX, IVR, VOIP system, etc. That is the CPN number. 66.114.93.6 (talk) 06:35, 2 October 2009 (UTC) es not significantly limit your choices for setting the calling party number. Hence, it is easy for a PBX administrator to unscrupulously spoof the calling party number. Bellhead (talk) 20:02, 7 October 2009 (UTC)

There is something called the BTN field, which is typically inserted by the originating switch and is used internally and not generally released to the public or the endpoint. Years ago, the BTN would be either your (CPN) number or at least in the same exchange. That worked great since the company that owns the number is also the company terminating the call. Perhaps this is what some people I hear refer to as "real ani". Today where increasingly the CPN number is not owned by the company terminating the call, and even the company you pay may be even terminating your calls via various wholesale providers, the BTN will be vastly different than your CPN number. The BTN will only will be the area code and exchange IDing the switch that originated the call into the PSTN and not a real number. 66.114.93.6 (talk) 06:35, 2 October 2009 (UTC)

As already described the billing telephone number is ALWAYS released to a toll free number as the ANI information. The service provider who owns the calling party number associates the billing telephone number and passes them both to the next service provider. They should be reasonably associated although it may not always appear to be the case. For example, its possible for a large company to have many different numbers all with the same billing number. The billing number is frequently the one ending with many zeros. Could this be what you identify as the exchange? Bellhead (talk) 20:02, 7 October 2009 (UTC)

For whatever reason ANI is frequently confused with the CPN and/or BTN. ANI originated from 60's technology, in which CPN and BTN replaced it years ago. ANI worked like it did because pretty much all phones were hard wired and each area only had one phone company, so you could transmit the assigned phone # of the pair as ANI information. One popular use of ANI data was in fact for business tollfree systems to have an early caller id like system to get the caller's number. Seems as people still believe this is in use in which this may be some of the confusion with 800 numbers even today being able to not block caller id from them. Today from what I know about SS7 signaling is that the CPN is simply just a call back number, which is used to populate the caller id display. The BTN on the other hand is for internal billing purposes for the carriers passed from switch to switch - and this may be some more of the confusion with 800 numbers. I can say that the BTN is used to determine the actual originating switch to bill the correct rate. I never heard of or thought the BTN information would be released to the 800 #'s end point. From what I know it takes court orders to get BTN information from carriers. Any company wishing to have the caller's number showing on their screens and logs with a tollfree # or otherwise; the number doesn't matter. They are receiving the CPN data directly. They do not have to honor Privacy flags so the numbers are still logged, spoofed or otherwise. It is as simple as that. 66.114.93.6 (talk) 04:00, 1 May 2010 (UTC)