Why do I get robocalls from recently-called area codes?

for voice calls, the best thing I ever did was set up my own asterisk system with a DID that answers as an IVR saying something like "you have reached $NAME, this is an anti-spam system, please confirm you are a human by entering the digits five three zero nine to be connected".

If people then put in the DTMF tones for 5309, or whatever code it might be this month, it initiates an outbound call to my actual cellphone and bridges the calls together.

In many cases I don't give out my direct cellphone number to 3rd parties, or anyone who isn't a close family member or colleague, I only give out the DID of the system with the filtering IVR on it.

I do still receive the occasional coldcall spam on my cellphone's direct number, which isn't entirely avoidable, but those are only random calls which aren't looking for me in particular. By only giving out the phone number of the filtering DID, I avoid my number being entered into many random third parties' CRM systems which are inevitably subject to data leaks, copying, data sharing with other 3rd parties, sales and marketing campaigns, etc.

As a counterpoint, I frequently get robocalls from area codes near where I travel. I recently visited Virginia and received robocalls from Virginia area codes for a while. A couple years ago I visited California and received more than the usual number of robocalls from California. A few years ago I visited Seattle and received robocalls from Washington. I most recently moved within Texas and the constant robocalls changed area codes to the more common local one.

I really _really_ wish I could flag an incoming call to my telecom provider and get paid money for it charged to the caller. Then let the telecom provider prove that it was or wasn't malicious.

Maybe their spam filters block many of these robo calls but they let them through if you had some recent contact in the same area/digits?

For a few years I have been experimenting with some creative anti spam manual techniques. Hard to say if they are working but these days I do rarely get spam calls. What used to be multiple per day is now down to about one. Could be coincidence however.

1. Often I will end an incoming call as fast as possible if it seems like a spammer. When you do this while the first ring is happening sometimes a few seconds later you will receive a second call from the same phone number. I then end that call as fast as possible again (without answering of course). I am hoping that some of these spam phone software systems have automated processes to mark numbers that are no longer dial-able.

2. Sometimes I answer as fast as possible and then play the oldschool sounds of a dialup modem or fax machine. I have even jokingly done this just making the sounds of a dialup modem with my voice. Many times the automated system hangs up after I do this. Again I am hoping they have something built in to their automated spam system to mark numbers that are fax / modems / non-people.

3. I have also tried answering the phone and then completely covering the mic or playing some simple white noise. This does not usually seem to work and eventually someone picks up. I doubt they are marking my number in this case as it has gone to an actual human.

mobile or landline? If landline is your phone capable of displaying Caller ID? If yes, can you check the firmware of your landline phone as Caller ID uses v23 protocol, so your landline has dialup modem abilities and anyone with access to your landline could remote control your landline phone. Had the data and time changed on my landline phone in my case, just someone showing off their full spectrum dominance!

If landline has your phone company been hacked or your security services yanking your chain?

If mobile, is your device rooted? Is you sim card hacked? Any component with a cpu may have the ability to independently use the hardware, so a sim card phoning home independent of the phone OS, it all depends on how the circuit board is designed.

Your phone is listening and it's not paranoia (2018 https://news.ycombinator.com/item?id=28973345

LTE Phone Number Catcher: A Practical Attack against Mobile Privacy https://www.hindawi.com/journals/scn/2019/7425235/

Not the link I was looking for but it will probably convey the same info which is your Decap of a Cell Phone SIM card [video] https://news.ycombinator.com/item?id=12674846

And dont forget the arm processor used for wear levelling purposes in (micro)sd cards, also another attack vector depending on how its wired.

Update: today I received a text message about booking air travel while I was still on the phone with an airline.

I called my cell carrier and they said that even they do not have my phone records until several hours later, and besides they don't sell phone records.

When I called Apple, the senior advisor told me that maybe my Facebook app is listening to me since "that's just the way the systems are set up". I was floored that an Apple employee (a senior rep, no less) would say such a thing. She didn't indicate how the app would have permission to do this if not granted it at the OS level. Regardless, I don't even have the FB app installed.

I'm now going to swap my SIM card into a different iPhone and see if the issue persists.

If you look up the carrier of each number you called, are there any commonalities across them?

Have you opted out of CPNI resale in your cellular carrier’s preferences system?

Who did you talk to in these area codes? Was it, for example, a call center for a business or another automated system that could have sold your number to someone? If it was a personal contact then I'd write it off as a coincidence.

Is there an app on your phone sharing your call logs?

Really not sure what's going on there. Tempted to chalk it up to a funny coincidence, but it doesn't seem like it.

I'd chalk it up to an app on your phone tbh. Android is particularly susceptible to this if you have READ_CALL_LOG permission on for some apps.

We might need more information.

I get a number of local code spam calls, but have seen an increase in state code calls.

Are the area codes you're seeing local to you, or distant? Or, what's the likelihood that someone in your region would be calling the same area codes?

Do you have any apps installed that have permit to access your dialer or contacts app?

Welcome to the club. They know when I get off work and wake up now.

I used to! Two things that have made a big difference:

1) Pay for a real spam filter from your telecom (usually free in highest tier plan). It’s remarkable hope much it catches, and I have never received a complaint in 5+ years

2) Buy a long term burner— your telecom usually sells a reasonable plan, or free if you pay for high tier coverage.

Me: same cell # for 25 years-22 too many with sprint (good spam shield when it didn’t crash) and more recently t-mobile (great spam guard and burner (named Digits)—both free upon request if you have a sufficiently expensive plan)

To piggyback on this thread, does anyone know if I can block a specific phone number provider (e.g. block all Twilio calls)?

does anyone know who is the telecom company that provides routes the calls from the robocallers?

Which carrier do you use ?