Fax and mobile phones: the full picture

A mobile can be used to send a fax, not to take one.

Behind the phrase “fax and mobile” sit two distinct questions that call for opposite answers. Outgoing fax from a smartphone raises no issue whatsoever: the device serves purely as a display where you complete the Faxeroo form and attach the PDF, since the communication is launched from our platform. On the other hand, no provider can get a fax through to a mobile number. The protocol requires a fax machine that picks up and negotiates using audio signals; a mobile, for its part, alerts its owner, and the cellular network damages those signals along the way. Faxeroo therefore accepts landlines only.

What stops mobile telephony from carrying a fax

At the start of a transmission, the two machines recognise each other by standardised whistles: a calling tone on the caller's side, an answer tone on the called side, then an inventory of their respective capabilities (resolution, speed, format). With no answer after around thirty seconds, the caller gives up. A smartphone emits none of these tones: it alerts its owner in their pocket.

Suppose nevertheless a fax machine hooked up behind a SIM card. Such a call would travel through voice codecs (AMR, EVS) built to retain only what matters in a conversation. To the ear, nothing changes. For a modem, which writes information in the phase and amplitude of its signal, it is a deluge of errors: the link collapses within seconds.

Fixed networks that have migrated to IP came up against the same obstacle, and overcame it through the T.38 standard, which transports fax data instead of fax sound. Mobile operators do not provide it on their consumer plans: only voice remains, and voice fails.

Three situations

Behind the search “mobile fax” almost always lies one of these three needs.

  • Sending from your phone

    No difficulty at all. Open Faxeroo in Safari, Chrome or Firefox, upload a PDF or photo stored in your files, then enter the recipient's fax number. The communication leaves from our platform: nothing is deducted from your plan, no app to download, and one page goes out free.

  • The recipient only has a mobile

    Without a landline, they have no fax machine. No point persisting: send them the document by email or messaging. Fax remains useful for reaching a government office, a practice or an organisation that owns the machine.

  • Checking your faxes on mobile

    For that you need a virtual fax number, obtained from a specialist operator: it captures the faxes and sends them back to you as attachments. Faxeroo concentrates on sending and allocates no number; the page devoted to receiving details the solutions available.

The check applied on entry

Before any transmission, Faxeroo checks that the number entered follows the landline format of the country selected. In France, an entry starting 06 or 07 is ruled out with an explicit message, even before the confirmation screen. A documented limit of the filter: Canada does not use distinct prefixes for landlines and mobiles, so the filter cannot distinguish them automatically. In that case, ask the recipient to confirm that their line is indeed a fax machine's.

This blocking saves you time. Without it, the send would exhaust itself in repeated attempts, or wake a stranger's mobile, which would hear nothing but whistles. A clear refusal is better than the illusion of a document on its way.

Fax and mobile: frequently asked questions

Some services advertise fax to mobiles. How do they do it?
Nothing of the sort: these offers send the mobile an SMS with a link where the file can be downloaded. The recipient has to own a smartphone, click, and accept the download. The fax machine plays no part, and no proof of delivery is issued.
Can an SMS or WhatsApp stand in for a fax?
Sending a document to one person? That works, and it's frequently the easiest option. However, such messages don't count as faxes: the recipient's device sends back no acknowledgement, and plenty of organisations won't accept files delivered through chat apps.
How do I send a fax from iPhone or Android?
Straight in the browser, with no installation. On Faxeroo, fill in the form, attach your file — PDF, photo, Word, up to 100 MB — and confirm. A confirmation email arrives: click its link within 3 minutes, then follow the transmission from the same phone.
How do I spot a foreign mobile number?
Mobiles live in reserved ranges: 06 and 07 in France, 04 on the Belgian side, 015 to 017 in Germany, Italian numbers starting with 3. Faxeroo's dialling code directory details the correct format country by country; in Canada, only the recipient's confirmation counts as proof.

Fax in everyday life

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