At my job, I do a surprising amount of faxes for people. Faxes are mostly still used for insurance and government paperwork (IRS, govt. employee pensions, etc.), and some people rely on them heavily. But faxes take a long time, are unreliable, and our machine in particular loves to grab two pages at once so I have to manually feed in each page as it goes.
One day I realized, there has to be an app for that, right? And I was right - tons of them, in fact! But, despite looking at dozens, I wasn't able to find any that fulfilled the basic functionality I was looking for.
Every fax app I found was the exact same - you pay a - to be fair quite reasonable - monthly fee for a virtual fax machine with its own phone number, only accessible from within the app. From the app, you can send PDFs, JPEGs, TIFFs, or any other still visual medium to any other fax number. This is all automated, if the fax fails you can tell it to resend immediately or send again at a specified time. You get notifications on the process. You receive faxes the same way you send them, as PDFs or TIFFs, with notifications and all. Very useful, indeed.
But why do you have to pay for them? Why do you have to get a virtual second number? What I've been hunting for is a fax app that is as dead simple as can be, and shouldn't require a monthly fee (though I wouldn't be opposed to paying up front for the app or donating to the developers).
The modern fax machine is, when you break it down, just a modem that specializes in sending documents rather than any other kind of data. If you've ever used a fax machine, or accidentally dialed one, you've heard the same screeching you hear from internet modems of yore - digital data modulated in audio frequencies that can be carried by phone lines.
So why can't your smartphone just... do that? It's already got a phone number and a connection to the phone network. Let me download a simple app that sends faxes using my smartphone's number. This seems an easy idea.
I imagine the only reason nobody's ever done it is because, usually when you send faxes from a number, people assume you can send faxes back to that same number.
But why wouldn't you be able to? I'm not sure if it's possible, but it seems like you should be able to have a fax app with the right permissions listen to calls from unknown numbers, and if it hears a fax machine handshake, it can just take over the call from there and receive your fax in the background. Right? Well, maybe not - I know Android broke call recording apps a long time ago, and this functionality is basically the same thing. Maybe you could only do it on a rooted device.
But it seems like it should be feasible. So feasible I'm almost certain it has been done before, I just haven't found it.