Bizarre audio loop on US-to-overseas phone call. Evidence of recording?
February 5, 2017 12:51 PM   Subscribe

Executive summary: on a couple of telephone calls I made today from a US landline to an in-country cell phone number overseas, the person I was talking to cut out about a minute into the conversation. After a few seconds of silence, about 15 seconds of her previous conversation repeated on a loop, more than once. What's going on?

Full details: I'm in the USA and have a family member living in the Middle East (not one of the seven countries on the recent travel ban list, but still—Middle East). Ordinarily we communicate via Skype, but today Skype was wonky so I phoned from our landline to family member's cell phone (which has an in-country phone number). After maybe 30 seconds to a minute of decent audio, something bizarre happened: family member's voice cut out, and then I heard about a 10-to-15 second loop repeating a portion of her previous words (just her side of the conversation, not mine). This happened a couple of times. So I hung up and tried another call—same thing happened. Clearly this means that the call was being processed in some way that retained at least a portion of the conversation. So: has this happened to anyone else out there, and is there a benign (at least relatively) technical explanation? Or is it prima facie evidence of ongoing telephone surveillance that was glitchy at one end of the call or another?

For what it's worth, none of the content of this or any other phone calls we've had is anything that could be at all problematic. But if this does indicate recording going on beyond the technical requirements of overseas phone calls, I don't know whether to be more alarmed at the thought that it is part of routine procedure or the possibility that it is targeted.
posted by Creosote to Technology (7 answers total) 2 users marked this as a favorite
Most likely a buffer error on whose part I have no idea. Generally during call transfers sone of the data is kept to allow a smooth stream, think like a YouTube video, but not the whole thing. Most likely something at a tower malfunctioned and kept sending what it keeps in storage before being overridden.

That does not mean the call wasn't surveillanced, the US has made it pretty clear that they can and do screen calls regularly.
posted by AlexiaSky at 1:10 PM on February 5, 2017

Did you or the other person somehow send it to your voicemail?
posted by Seeking Direction at 1:10 PM on February 5, 2017

Tech explanation: VoIP traffic is often UDP, which means it will retransmit if if errors are occurring.

Non-tech explanation: If your internet connection is poor for whatever reason, anywhere between you and the other person, the technology involved will detect it and try sending the same data (your conversation) again to make sure it gets through. Sometimes this results in delays, and sometimes it results in stuttering or repetition depending on how aggressively the program tries to re-send the data.

Line taps of internet-based communication are seamless -- the line is split somewhere in the middle and the data is copied, and that duplicated data is sent to a second destination. It would not result in the copied data getting sent to you twice.
posted by erst at 1:23 PM on February 5, 2017 [6 favorites]

It is far more likely to be proof of crappy network/digital phone systems (not that landlines didn't do this, international calls were a nightmare long before voip) suffering lag and compression issues. Network routing systems do re-tries all the time - it's all just packets, you hold them in a buffer and push them through, and if you don't get acknowledgement that they were received, you send again. This happens to me on every gotomeeting I'm on, and phone calls inside my own office.

Yes, you should always assume that your communications are being recorded unless you are taking precautions, but what you experienced is not the evidence that you were.
posted by Lyn Never at 1:25 PM on February 5, 2017

In the worst case echo cancellation software needs a buffer of about a half second , so normal telephone voice buffering is not long enough to explain what you heard. However, as erst explains, it is possible that at some point your voice call was being routed through a packet network that carries both voice and data and some device in the packet network was configured with a very deep buffer.
posted by RichardP at 1:27 PM on February 5, 2017

My first thought was that the repetition had to do with buffering, because it was very similar to repetition loops I've had with Internet radio for example. But I wasn't sure that landline-to-cellphone calls could be subject to this. The responses clear that up, thanks!
posted by Creosote at 2:48 PM on February 5, 2017

VoIP does commonly use UPD, but UDP does not error check.

It is a fact that the Internet is being actively monitored by governments. Whether that was the cause of your loop, who knows.
posted by LoveHam at 8:38 PM on February 5, 2017

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