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Ask HN: Why can't I send faxes from my phone?

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Re: Ask HN: Why can't I send faxes from my phone?

#61

Post by mattrp »

tjohns wrote: post #33
mattrp wrote: post #11

Earlier quoted context omitted.

Fax has an ip protocol called t.38 however it is inconsistently implemented. Most services still rely on g.711 - essentially uncompressed voice - for transmission of fax tones. However there is no guarantee the end to end call will be g.711 even if specified during call setup. There is an app called eFax - unfortunately the service is not free but I as a subscriber routinely fax over the phone when it’s the only way…

While G.711 is uncompressed (it’s the same codec used within the PTSN backhauls), it’s still not great for fax because the fax protocol doesn’t tolerate the jitter introduced by VoIP. (Reliable latency is the one big benefit to switched networks like the PTSN.) As I understand it (and I could be wrong), T.38 solves this by emulating an independent fax modem on each side of the analog connection, and only sending the…

You’re right g.711 is not ideal either. Jitter is a killer. T.38 is a solution when it’s supported on both sides and it is often not. The best solution is email but apparently every title office and pediatrician in the land cannot be bothered! ;) Although thankfully many have moved on.

Re: Ask HN: Why can't I send faxes from my phone?

#62

Post by colinbartlett »

ceejayoz wrote: post #30
rabidonrails wrote: post #16

Founder of Phaxio here. Doing fax well is an annoying problem because the protocols are finicy and the carriers don't usually want to spend time troubleshooting issues. Give our API a shot and shoot me a note for some extra credits as a h/t to a fellow HNer. (See profile for email.)

I used your service a few times when buying a house. One cURL call and it was done. Super easy and much appreciated.

I am amused and impressed that you chose an API and cURL to send a fax than any of the many apps and services built on top of that API.

Re: Ask HN: Why can't I send faxes from my phone?

#63

Post by ceejayoz »

colinbartlett wrote: post #62
ceejayoz wrote: post #30

Earlier quoted context omitted.

I used your service a few times when buying a house. One cURL call and it was done. Super easy and much appreciated.

I am amused and impressed that you chose an API and cURL to send a fax than any of the many apps and services built on top of that API.

At the time, all the ones I could find were like $1/page or more like a $30/month subscription.

$0.05/page was well worth a cURL call, especially when the docs had great examples that just needed me to swap out the file name for mine.

Re: Ask HN: Why can't I send faxes from my phone?

#64

Post by uranium »

colejohnson66 wrote: post #58
gumby wrote: post #29

Earlier quoted context omitted.

In the US, clinical medicine and law firms use it because it has an unusual legal status: it’s considered secure and positively delivered if some device at the other end acknowledges it. In Japan many businesses are still wedded to a fax. It’s much easier to scribble a take out order on a piece of paper.

How is it secure though? It’s unencrypted!

It's point-to-point. Unless someone is tapping your phone line, or you dial the wrong number, where's the insecurity?

Contrast that with email, which goes through any number of emails, sits in queues, gets backed up, etc.

Of course some of the time you're actually faxing a fax-to-email gateway, but ¯\_(ツ)_/¯.

Re: Ask HN: Why can't I send faxes from my phone?

#65

Post by CyberFonic »

The technology problem is at the fax machine end.

Fax machines have embedded modems which decode and respond with a complex set of tones to transmit and receive data that makes up the facsimile image (yup, it's all images to the fax and that's why they still use them).

Smartphones are all digital so you need a gateway to convert digital signals to suitable analog tones to satisfy the fax machine's modem. Conceptually you could implement the gateway functionality as an app because we can still transmit and receive tones, i.e. voice calls. Quantisation and delays might still introduce errors, but the fax protocol does have some basic error checking and re-transmit capabilities.

Re: Ask HN: Why can't I send faxes from my phone?

#66

Post by rsynnott »

gumby wrote: post #29
talles wrote: post #19

Genuine question: why there are folks still using fax?

In the US, clinical medicine and law firms use it because it has an unusual legal status: it’s considered secure and positively delivered if some device at the other end acknowledges it. In Japan many businesses are still wedded to a fax. It’s much easier to scribble a take out order on a piece of paper.

Due to the GDPR (most regional regulators do not consider normal fax to be secure, and of course it creates otherwise unnecessary paper copies of data) medical systems in Europe are being slowly weaned off it. I gather a lot of doctors are putting up a fight.

Re: Ask HN: Why can't I send faxes from my phone?

#67

Post by CyberFonic »

throwlaplace wrote: post #32
gumby wrote: post #13

The fax requires a 56KHz channel which has not been used for mobile telephony since the 1980s (when AMPS and GSM were developed. Before then it was just a radio link through an operator). That’s why you can’t use a high speed modem either. Some gsm phones had the ability to transmit a fax but they actually used a different protocol to talk to a fax gateway. I never saw one of these in the wild. I haven’t been in that…

>The fax requires a 56KHz channel hmm so you're basically saying that fax machines only listen to data coming across on a 56KHz carrier wave? i guess that makes sense since the same device (a fax machine) can function both as a telephone and fax (and you'd need to distinguish in hardware which mode you were operating in upon "picking up the phone"). but what i don't understand is the telephony (i'm not a network engi…

It isn't a 56kHz channel. It is a 56k bps channel encoded as complex tones onto a 4kHz voice connection. The telephone system wiring does not have the bandwidth to carry a signal that is 2-3x the range of human hearing.

Re: Ask HN: Why can't I send faxes from my phone?

#68

Post by rsynnott »

gambiting wrote: post #37
talles wrote: post #19

Genuine question: why there are folks still using fax?

It seems to be the same as cheques and magstrip-only cards - uniquely American thing that rest of the world hasn't seen in years. I do remember not that long ago opening an apple developer account required filling out a form with your card details and faxing it to some US-based number. It was madness back then already.

I remember in an old job we didn’t have a fax machine... Until we started opening a US office, because apparently it’s pretty much mandatory there.

Re: Ask HN: Why can't I send faxes from my phone?

#69

Post by rsynnott »

ken wrote: post #34
mceachen wrote: post #7

Earlier quoted context omitted.

HQ audio quality (over 4G) is markedly better than land lines, and the fax protocol has had error correction since digital formats were adopted in the 60s and 70s. https://en.m.wikipedia.org/wiki/Fax My Palm Pilot (with a CDPD backpack) and candybar 2G Nokia could both send FAXes. I suspect there's no demand.

> HQ audio quality (over 4G) is markedly better than land lines This is one of those facts that, no matter how many times I hear it or what proof is offered, I find it impossible to believe.

... Wait, why? Standard landlines are 300hz to 3.4khz; pretty low-fi. They should not be particularly hard to beat. VoLTE certainly sounds better than them.

Your network or device may still be using the 90s cellular voice standard, tho.

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