Since everyone has been so helpful with research answers, here’s another one!
So here’s the (fictional) scenario from the paranormal mystery novel…
Victoria has been getting weird, anonymous phone calls for a couple of weeks. The actual content of the calls isn’t annoying or harassing as such-- the person keeps assuring Vic that he’s a friend who wants to help her. It’s been totally impossible to trace the calls, because… (eerie music) no phone number at all has ever shown up, and there is no way to find any record that the calls were made.
I’ve researched some information about harassing phone calls, but I’m not sure what would happen in this scenario. Is there any actual way for an anonymous caller to completely mask their phone number and even the fact that they called, no matter what anyone does to try to find it out? And in a case like that, what would the attitude of police, phone company, etc., likely be? Would anyone start to think that Victoria is just nuts?
I ignore it as much as possible. Instead, I try to find cute kitten-and-sloth videos. See, there are lots of kitten videos, lots of sloth videos, but so far, nothing of the two of them together…
Anyway. In a way, this is the opposite. Nobody can trace these calls.
It can be done now. There are rules at this board against posting details on how to break the law, so I’ll stop now. Google should give you plenty, if you’re persistent.
I don’t know what the cops or phone company would do. Nothing the caller would like, if caught, I suspect.
There is a difference between no originating phone number and no trace of the call.
Sadly it trivial to fake the originating phone number, it isn’t even clear it is illegal to do so. I get nuisance calls (fake Windows support scams from India) - once one was from the number 0123456789 - which I thought was an impressively stupid thing to pick as a spoof. Most phone systems provide a mechanism to suppress sending the phone number, which is implemented at a range of stages, usually the mechanism only suppresses the number on the last leg to the recipient. (Emergency services can often see suppressed numbers, and this becomes an interesting issue when the police set up anonymous tip off phone lines.)
Lack of any record of a call at all is much harder.
Back in the days of analog phone systems and mechanical exchanges they systems were primitive enough that knowledge of the systems would allow a person to spoof numbers, or make calls that were essentially invisible to the billing system. Such calls would be untraceable once completed. This was the province of the phone “phreaker”. The guys the indulged in such hobbies were breaking the law, and some went to prison for the privilege. Such luminaries as Captain Crunch. However all that is ancient history. The systems now don’t work the same way at all. The big change is the movement from in-band signalling to out of band (something that came with digital phone systems). The old analog systems used to send control information along the same lines as the phone calls were being placed on, and simply used secret protocols of audible tones to effect this control. If you knew the codes you could essentially control the phone system enough to make free and untraceable calls. Now you can’t. Everything is digital, and your phone calls traverse data networks, and are controlled by essentially specialised computer systems. The level of logging possible is huge. With a demonstrated need no phone call to a given number could occur un-logged.
Phone companies can provide a range of services to people that get nuisance calls. One is call screening (only set up when there really is a serious problem) where all calls can be diverted to a human operator who will screen the calls and forward them on to the recipient if appropriate. If there was a such problem it would be impossible to spoof the system enough that a call could get through unlogged. The origin of the call could however still be difficult to impossible to ascertain. Such a diversion is set up on the exchange frame that the callee is directly attached to. There is only wire between their phone and the exchange.
However there does remain the trivial brute force approach to making such a call. Tap into the phone line in the house. The call would never actually happen on the phone network. Even here the phone exchange could be set up to log changes in the state of the phone line, and could notice something odd when the call happens. Modern exchanges have the ability to act as a time domain reflectometer, and can test the physical line to a remarkable level of precision. They can see the presence of individual handsets on the line, and could see nefarious activity on the line associated with the spoofed call.
We are moving rapidly to a new ear of voice calling however where things will change again. As voice over IP (VOIP) becomes ever more popular, things will get to the point where calls and call origins may be essentially untraceable and impossible to log.
Oh, and use of a cordless handset obviously opens up another whole swag of spoofing possibilities. So you had better make sure it is an old wired handset your heroine uses.
If you contact the phone company, they can put a trace on your line and record the source of all calls. Note that this is done with an internal system called ANI (Automatic Number Identification), not CID (Caller ID, the consumer version of the same function). They will hold this information until they get a court order to release it. I don’t believe ANI can be spoofed unless someone has internal connections to the phone system.
This works for domestic USA calls. I’m not sure how well it works for international ones.
I have a magic jack number I bought at a wally world for cash that connects over a foreign VPN. I’m guessing that’s going to throw a wrench into things.
All the fancy tapping is going to do nothing for a burn phone. Heck, I even have a burn phone [for Germany, not the US. I love cash deals and buying minutes with cash. I might even get one for the US at some point in time.]
The phone company would be upset that somebody was using their networks without their knowledge (and thus, approval). They could complain to the police who would be obliged to investigate this violation of the Computer Fraud and Abuse Act (aka hacking).
After their investigation turned up nothing, then they’d probably consider the possibility that Victoria might be hallucinating or something, but they’d need some other evidence that she’s mentally unstable to assume that from the start, especially if there’s a plausible reason somebody would go to the effort to contact her in this way.