Why can't I send faxes from my phone?

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 give up and tell them I can't send a fax where I'm from. When they ask where I'm from, I tell them I'm from the year 2020.

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 “biz” for a couple of decades but nowadays a different approach will be used anyway (pdf via IP to a fax gateway -> POTS)

Faxes rely on modems. modems rely on precise timing and aren't able to cope with any slippage.

There's actually a protocol, T.38, which is used on modern VoIP based systems to allow faxes to be transmitted. At each end it actually decodes the fax data and sends it as ordinary data packets. Implementations play some tricks on the fax modem at each end, in order to prevent it dropping out of sync if the data packets are delayed. You could communicate with one of these from phone, but you'd need a T.38 gateway a the other end.

More practical is to cut out the middleman and use twilio's fax gateway at $0.01/page (+ sip trunking cost, which should be similarly trivial): https://www.twilio.com/fax/pricing

To send a fax you need access to a handhshaked landline. A direct wire between the stations. Faxes synchronize themselves, send data and test the bit, makeing sure it is properlt placed in the data queue, and send the next and so on =handshake. Suggest you look up old fax synchronization and I tossed my last muirhead rotary in 1982 - used it for weather maps.https://electronics.howstuffworks.com/gadgets/fax/history-of...

Newspapers have used it since the 1800's in one for or another. Wire-Photo https://antique-photos.com/en/helpful-info/476-wire-photos.h... This is a relic of the old Muirhead rotary scanning fax machines abd the same standard persists. This is hard to do via radio. So radios send a pdf to a fax service. I have a fax service for $10 a month, I send it via desktop or mobile, and receive the same way as a pdf. With a mobile printer or office printer you get hard copy. https://www.myfax.com/features

This used to be possible over GSM, at least in the UK, and so I assume most places that use(d) GSM.

I did it from various generations of the Nokia Communicator. The phone would initiate a special kind of phone call (from memory, the same AT string used to start an ISDN connection) and then send digital data over the link, not audio tones directly.

This would emerge onto the analogue phone network as fax tones.

I suppose it's possible that the cellular networks simply don't support this anymore, but my first guess would be that it's handsets that lack the software to do it, now.

It doesn't have to be expensive or complicated. I've written a simple web app that wraps Twilio's fax capabilities.

https://github.com/fastily/fax-machine

The whole thing is designed to run on a raspberry pi. The setup costs $1 a month (for the twilio number) and a couple cents per page.

Some older cell phones were capable of sending faxes. I don't know why today's phones don't have that option anymore.

My wife had one of them in the mid-2000's. It was a SonyEricsson, but I don't remember the model number. All I remember was that it was mustard in color and impossibly small.

A quick internet search shows that the SonyEricsson T39 had a GSM modem capable of faxing, but the pictures of it aren't what I remember from my wife's phone.

Given the percentage of "faxing" that is eFax to eFax, I wonder if we'll even notice when the last fax machine is turned off...

Genuine question: why there are folks still using fax?

Faxburner is free.

I've had good luck with Hellofax (YC company) for sending a fax from time to time. Not literally using your phone, however.

I wonder if you could hold up your smart phone to a landline handset like an acoustic coupler to send a fax?

When I first applied for the Apple Developer Program from the Netherlands in the early days of the iPhone when they first published the SDK, Apple insisted that I fax my registration in to them in the UK, so I had to print it out, and take it by a shop that had a fax machine, and pay several euros to send an international fax to Apple.

More than 10 years later, there's still not an app for that.

My IP phone provider, Voyant, offers a fax api: https://www.voyant.com/product/fax/

So if you can write an app that accesses this API, you can send faxes. It would be easiest to do this as a web service that you can access from your phone via a web page.

There used to be a free service for faxes, at tpc.int.

https://en.wikipedia.org/wiki/The_Phone_Company

The fact that it costs you so much probably just means that the demand just isn't there.

How about a service that can grab a document out of your Dropbox or other cloud account, then fax it for you? $10 for 50 pages could result in hella margins, if it's done right. (Everything done digitally, of course.)

The account could even be managed from a phone app.

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.

You could when your tablet was a Newton.

I remember a long time ago when I worked for a voip phone company, two of our customers asked for fax-to-email and email-to-fax.

I found out they were trying to fax each other documents because of some archaic requirement and thought it was the most hilarious thing ever. Totally just sending each other emails with extra steps for no reason.

as aurizon stated you have to have an intermediary. There are several reputable email to fax services like fax.plus that will allow you to send up to 10 pages for free each page after that is .20 cents. apologies, it's frustrating when you can't other forms of e comms.

Already a solved problem - https://www.ringcentral.com/fax/features/how-it-works.html

Not the most elegant solution, but the price is right. Anveo.com has plans for about $2/month for their VoIP service. And a web based outbound fax that has worked well for me. No extra charge for the outbound fax.

Would even Android allow that kind of access to your phone from a program?

I am partially confused.

Is "fax by email" dead or otherwise unattractive?

hellofax.com works for this. I just used it a couple weeks ago took a minute to send a fax live to the receptionist.

Faxzero is a great mostly free solution.

This question feels and reads from the past...

The lossy compression on phone calls might prevent fax from working. Also, I don't know if you can route call audio from anywhere other than the microphone.