International faxing: why your transmissions fail from one country to the next

Short answer: when a fax goes through to France without a problem but fails to Germany, Italy or Canada, the cause is rarely the number. It is almost always in the transport chain: the destination country has migrated its network to all-IP, an intermediate gateway is degrading the signal, or the receiving fax machine is negotiating a speed the link cannot sustain. The three reflexes that solve the majority of cases: check the strict international format (+ country code, national number without the leading zero), force a low speed (9,600 bit/s) and enable ECM error correction. The rest comes down to national specifics, detailed below.

About MondialFax. This article is an independent technical guide. MondialFax sends faxes free of charge and without registration to seven destinations (France, Belgium, Germany, Spain, Italy, Portugal, Canada). It does not assign a number and does not handle reception: the receiving scenarios mentioned here assume a third-party provider. See receive a fax and our fax-to-email guide.

There is a sentence you hear all the time in export departments, in law firms working across borders and among freight forwarders: "it works for us, but not to Italy." It is irritating because it sounds irrational. Fax is a standardised protocol — the ITU's T.30 recommendation dates back to 1980 and its underlying logic has not changed since. A fax machine in Milan and one in Lyon speak exactly the same language.

Except that, for the past fifteen years or so, they no longer speak through the same telephone. Between the two machines there is no longer a continuous copper circuit, but a succession of analogue → digital → IP packet → analogue conversions, carried out by equipment designed to transport human voice, not trains of modulated tones. And every country handled those conversions at its own pace, with its own technical choices.

That is where the failures hide.

Step 1: rule out the dialling problem

Before any technical consideration, you have to eliminate the most mundane cause — and by far the most common one. One in five international faxes fails because the number is badly formatted.

The zero rule

The leading zero of a national number is never dialled after a country code. A German number written 030 12345678 is dialled +49 30 12345678. An Italian number written 02 1234567 is dialled +39 02 1234567 — and that is the exception that catches everyone out: Italy keeps its zero in the international format, unlike France, Germany, Spain or the United Kingdom.

Spain and Portugal have no leading zero: their numbering is a closed nine-digit plan, which simplifies everything. Canada shares the +1 country code with the United States under the North American Numbering Plan (NANP) — so a fax to Montreal is dialled exactly like a fax to Chicago, only the area code changes.

The international access prefix

From an analogue fax machine plugged into a traditional line, the + does not exist: you have to dial the international access prefix, which is 00 throughout the European Union (CEPT standard) and 011 in North America. From a company PBX, add the prefix for an outside line — often 0 or 9. Hence those endless numbers of the type 0 00 39 02 … that explain a great many "number unobtainable" messages.

Our dedicated guide covers the whole subject: sending a fax abroad.

Step 2: understand what each country has done with its network

This is the heart of the matter. "Country-specific" failures are not superstition: they reflect real migration timetables.

Germany: the most advanced migration

Deutsche Telekom completed the bulk of its switch to All-IP as early as the late 2010s. In practice, there are no longer — or almost no longer — any native ISDN or analogue lines in German businesses: the fax machine at the other end is plugged into the FXS port of a router, behind a G.711 codec at best, a compressed codec at worst.

The practical consequence: a fax to Germany succeeds all the better for being slow. Forcing 9,600 bit/s instead of the default 33,600 bit/s reduces sensitivity to micro packet loss. It is counter-intuitive — you think you are saving time by raising the speed — but a page that leaves at 9,600 bit/s and arrives is infinitely better than six attempts at 33,600.

Italy: the long tail of legacy lines

TIM (formerly Telecom Italia) carried out its migration more gradually, with strong regional variation. The result: you may be dealing with a correspondent still on pure analogue in Bari and an all-IP correspondent in Milan, without knowing it. The symptoms differ: on a legacy line, an Italian fax that fails is often a tone detection problem (the Italian busy tone has a different cadence from the French one, and some low-end fax machines misread it); on an IP line, it is the classic mid-page drop.

Spain and Portugal: all-fibre as the norm

Spain and Portugal are among the most heavily fibred countries in Europe. Movistar, Vodafone España, MEO and NOS have massively moved their business customers onto fibre access with SIP telephony. The consequence is direct: analogue fax has become rare there, and many fax numbers published on institutional websites are in fact virtual fax services that receive in PDF. Good news: these services generally accept calls very well, provided the negotiation takes place in T.38 or uncompressed G.711.

Canada: distance and codecs

To Canada, the fax crosses an international transit carrier. Transatlantic links add latency in the order of 80 to 120 ms, which is not a problem in itself for voice but can cause certain T.30 timers to expire on poorly configured equipment. The major Canadian operators — Bell, Telus, Rogers — have largely modernised their network cores. Here again: low speed, ECM enabled, patience.

France: the end of copper in the background

On the French side, the shutdown of the copper network led by Orange under the supervision of Arcep is proceeding batch by batch, with schedule adjustments announced regularly. For the fax sender, this means the originating line itself will eventually disappear. We covered the question of keeping your number in keeping your fax number after the PSTN shutdown, and the mechanics of T.38 in fax over VoIP: why T.38 fails.

Step 3: the settings that change everything

Here is the sequence we recommend, in this order, before blaming the destination country.

1. Lower the transmission speed. In the "Fax settings" → "Transmission speed" or "Modem speed" menus, drop to 9,600 bit/s (V.29). On professional machines, this option is sometimes called "VoIP compatibility" and handles the adjustment for you.

2. Enable ECM (Error Correction Mode). ECM retransmits corrupted blocks instead of abandoning the page. On an international packet link, that is the difference between an unreadable fax and a clean one. It is enabled by default on most recent fax machines but switched off on many entry-level multifunction devices.

3. Disable JBIG compression. This advanced compression is not understood by all equipment. On an international transmission, it produces silent failures. Fallback: MMR or MH.

4. Reduce the resolution. A page at 200×200 dpi (fine standard) goes through twice as fast as at 400×400. On a ten-page document to Canada, that can make the difference between a transmission that completes and a cut-off at page seven. If the source document is poorly scanned, the problem lies upstream: a decent document scanner with automatic feeder fixes more unreadable faxes than any modem setting. See also our guide on unreadable faxes.

5. Check the power supply and cabling. It sounds trivial, but a good-quality, short shielded RJ11 telephone cable prevents interference that shows up as black lines on the receiving end. The same goes for a telephone line surge protector at sites exposed to lightning.

Step 4: when the problem is no longer at your end

There comes a point where every setting is right and the failure persists. Three hypotheses remain.

• The number is no longer a fax. Many organisations have kept the number printed on their letterhead after unplugging the machine. The test: call the number from a telephone. If you hear a voice or a voicemail greeting, there is no fax behind it any more.
• The recipient filters international calls. Some switchboards block incoming calls from outside the country, particularly in the public sector. In that case you have to go through a local contact.
• The destination fax is saturated. A machine out of paper, with a full memory, refuses calls. This is common on Monday mornings in law firms and town halls.

In all three cases, the way out is the same: call the recipient. A thirty-second phone call replaces two hours of diagnosis.

Do you still need a fax machine to fax internationally?

Honestly, no — unless you need to receive on paper. For sending abroad, an online service removes half the variables in one go: no more analogue line at your end, no more conversion on transmission, no more speed settings. The provider's gateway is already sized for international transit and negotiates the best available profile with the receiving network.

What remains is preparing the document properly. A high-contrast black-and-white PDF, A4 pages, no grey background, always goes through better than a compressed colour scan. To scan on a daily basis without a multifunction device, a portable USB scanner or a simple smartphone scanning app is more than enough — see sending a fax from your smartphone.

And if the document is confidential — a medical file, a court document, a contract — the question of the channel arises before that of the country: our comparison fax or secure messaging sets out what each option actually guarantees under the GDPR.

Frequently asked questions

Why does my fax go through to France but not to Germany?

Because the German network is almost entirely all-IP. Your fax machine negotiates a high speed that the conversion chain cannot support. Force 9,600 bit/s, enable ECM and disable JBIG.

Should you keep the zero in an Italian fax number?

Yes. Italy is one of the rare European exceptions: the zero in area codes is part of the number and is dialled after +39. For Germany, France, Belgium or the United Kingdom, you drop it.

Does T.38 work everywhere internationally?

No. T.38 has to be supported end to end, or at the very least by the gateways at both ends. On an international call crossing several transit carriers, the negotiation often falls back to G.711 passthrough. That is acceptable if the link is stable and the speed low.

How long does an international fax take?

Allow roughly 45 to 60 seconds per page at 9,600 bit/s in standard resolution, excluding negotiation time (10 to 20 seconds). A ten-page transmission to Canada can therefore take ten minutes.

Does a transmission report carry the same weight abroad?

The transmission report proves that a call reached a given number, not that the document was read — and that limitation applies in every country. Its evidential value then depends on the law of the country concerned. See the legal value of fax.

In summary

• The number first: strict international format, national zero dropped except in Italy, international access prefix 00 in Europe and 011 in North America.
• The destination country determines the strategy: Germany and the Iberian Peninsula overwhelmingly all-IP, Italy heterogeneous, Canada penalised by transatlantic latency.
• Three settings solve the majority of failures: speed at 9,600 bit/s, ECM enabled, JBIG disabled.
• Resolution and scan quality matter as much as the modem: a clean document at 200×200 dpi goes through better than a heavy high-definition scan.
• When everything is right and it still fails, the problem is at the other end: a number that is no longer a fax, international call filtering, a saturated machine. One phone call settles it.
• For sending only, an online service eliminates half the variables — and removes any dependence on an analogue line destined to disappear with the end of copper.