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Comment by nothrabannosir | Hacker News Reader

You know how I can tell that I accidentally use the normal phone app, instead of voip, when I call my family internationally? Because the sound quality is good. Low latency, no dips, no buffering, smooth. To the point that my reflex is now: “hmm , the quality is too good, this must be the normal phone.”

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I make quite a few international calls on my phone every day in rural areas and in terms of quality and reliability I would rank the available options as: FaceTime > normal phone (I’m on Verizon) > Skype > most other VoIP > Google Hangouts (absolutely the worst).

Facetime Audio is so crystal clear for me that it feels like I am sitting next to my friend/family vs analog lines where there is generally an echo, and other weird delays. When I talk to my grandparents it always feels like we need to put pauses in our conversation to make sure we don't start talking at the same time.

doesn't verzion use VoLTE? which would mean that your normal phone app isn't your "analog" phone anymore.. (https://en.wikipedia.org/wiki/Voice_over_LTE)

Basically there aren't many phone calls over non LTE based services. Especially since VoLTE can be used over WLAN via Wlan calling techniques. (the latter isn't supported in all networks.)

VoLTE is only between your phone and your carrier; if you're calling someone on another carrier as far as I know it still goes over legacy garbage with a shitty codec (or worse, an analog link, with in-band signaling).

How do you tell if it's voip or not? A lot of phone operators use voip for calls. So choosing the default phone app doesn't necessarily mean that you are not using voip. And the phone operators infrastructure for voip is probably way ahead of most other call apps.

> A lot of phone operators use voip for calls.

I think the problem is that with "analogue" each jump can use a hodgepodge of their own voip going from Analog -> Digital -> Analog. So you can get multiple, lossy compressions with varying settings multiplied together. With user-initiated voip, it's a single compression over the whole connection. So it could be better than user-initiated voip, or a lot worse.

At least that's my laymen's understanding of legacy phone systems.

I'm pretty sure that most operators either use analogue or digital end to end, no mix.

VoLTE (Voice over LTE) have some other advantages over other calling applications. VoLTE is most likely on a very high QCI (priority), which means it probably has less delay and less packet loss than other traffic. VoLTE also often uses header compression over the air which means the packets gets a lot smaller and therefore also reduces packet loss. I don't think VoLTE usually have very high bitrate though, maybe around 10kbit/s. This is one area where other apps could be a lot better.

EDIT: I am of course only speaking about mobile calls. For landlines I agree that other applications provide better quality.

The issue is that VoLTE only works for calls made to the same carrier's subscribers, as soon as you call someone on another carrier it will go through a shitty interconnect with a bad codec (usually a variant of G711 which is a joke in 2017).

There is no such thing as analog telephony anymore, and there hasn't been for a long time. While you might still have analog local loops, the network has been completely digital for a long time, be it ISDN or VoIP, and VoIP is perfectly capable of transmitting ISDN voice data without recoding.

I think what might be being referred to as "analog telephony" is actually the "original digital" system using 64Kbps "uncompressed" PCM, vs. VoIP compressed audio at much lower bitrates. It's like the difference between CD and MP3.

I would be very surprised if any telco were using any sort of compression internally (other than G.711, obviously). 64 kb/s with RTP/IP framing overhead is about 100 kb/s, that's just not a lot of bandwidth anymore that it would be worth installing hardware to do de-/compression. Even a gigabit link can carry ~ 10000 such calls--that's a drop in the bucket compared to the internet needs of the many more than 10000 subscribers that you need to ever have 10000 concurrent calls (probably more in the range hundreds of gigabits, possibly terabits).

Really? My experience has been the opposite. I can tell I'm not on a Facetime audio call or what have you when the call is clearly undergoing the super lackluster compression used by the traditional system.

Not prior to 1990. Also, you are on digital with your mobile phone, the OP I was responding to was talking about old analog lines.

most POTS are digital and I assume a lot of them just put your call through some kind of VoIP today (not necessarily SIP)

Depends on the provider and codec. Who are you using for VoIP now?

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