The End of the PSTN: Your Analogue Fax Line in 2026

Short answer: the end of the public switched telephone network (PSTN, known in France as the RTC) is not a distant threat — it is a batch-by-batch shutdown schedule that Orange, under Arcep's supervision, is already well into. In practical terms, the wall socket that powers your fax machine will stop working on a date known in advance and announced by letter — a letter that all too often lands on the accounts department's desk and never reaches the person who actually uses the fax. Three actions, in order: (1) list every analogue line you have (fax, card terminal, alarm, lift, gate, remote-monitoring modem) before you even start thinking about the fax; (2) check your shutdown batch with your operator, asking for a firm date rather than "sometime in 2026"; (3) choose your destination — online fax by email/API, a T.38 gateway on a business router, or dropping the fax channel altogether in favour of a secure document drop. The trap isn't technical: it's plugging an old fax machine into a broadband router and assuming it works, when voice-over-IP compression destroys the very tones the fax protocol relies on.

What exactly is being switched off (and what isn't)

Two things that everyday language tends to conflate need to be told apart.

The PSTN is the historic circuit-switched copper network: your physical line establishes a dedicated path to the other party for the entire duration of the call. It is this network, and only this network, that is being shut down. Orange stopped selling new PSTN lines back in 2018, then began the technical shutdown geographical area by geographical area, batch after batch, under the watch of Arcep, which regularly publishes progress reports on the programme.

Copper as a physical medium is a separate matter, tied to Orange's copper network retirement plan, which runs through to the end of the decade. You can perfectly well lose the PSTN while keeping a copper pair carrying ADSL, or the other way round.

What matters for you: the day your batch switches over, the wall socket no longer delivers a dial tone. The fax machine plugged into it becomes a paperweight. It gives no warning and displays no explicit error — it dials into the void and prints a "failed" report that nobody reads.

And it isn't just the fax. In a medical practice, a law firm or a small business, the same family of analogue lines typically feeds:

• the fax machine;
• the backup card payment terminal;
• the alarm panel and its link to the monitoring centre;
• the lift emergency phone (a regulatory requirement for a permanent voice link);
• the intercom or the motorised gate;
• sometimes a remote meter-reading modem or a pharmacy temperature logger.

Taking an inventory of the fax alone is a guaranteed way to give yourself a second nasty surprise three weeks later.

Why plugging your old fax into the router isn't enough

This is the most common mistake, and an entirely understandable one: the business broadband router has a phone socket, you plug in the RJ11 cord, you hear a dial tone, you conclude that all is well. Then transmissions succeed one time in three, with truncated pages or black bands.

The reason lies in the protocol. Group 3 fax (ITU-T T.30) carries data as audio modulations designed for a linear analogue channel. Voice over IP, by contrast, compresses the signal with codecs optimised for human speech — G.729, sometimes G.722 — which destroy precisely the carrier frequencies used by the fax modem. Add jitter, packet loss and echo cancellation, and you get a transmission that fails halfway through page 4.

Three workarounds exist, in increasing order of reliability:

If you're set on keeping your existing hardware — because it doubles as a scanner and copier, because an institutional correspondent accepts nothing else — the sensible option is a T.38-compatible ATA adapter, configured by your operator or your network provider. Check that the feature is genuinely enabled on the operator's side: many offers list it in the catalogue without switching it on by default for SIP lines.

An additional setting that's often overlooked: drop the transmission speed to 9,600 bit/s and disable ECM error correction for troublesome destinations. You lose speed, you gain delivery success.

The line inventory: the one step you can't delegate

Before choosing a solution, you need to know what you have. This inventory takes half a day in a ten-person organisation, and it saves you paying for three phantom subscriptions for two years.

Step 1 — Get the itemised bills. Each line appears with its number and access type. Look for the wording "analogue line", "PSTN access", "main line" or "Numéris/ISDN" — ISDN is going the same way as the PSTN.

Step 2 — Walk the premises. Open the suspended ceilings if you have to, follow the cables. A rechargeable head torch and a network cable tester save a considerable amount of time at this stage, especially in premises where the patching was never documented.

Step 3 — Label everything. Every wall socket gets a label: phone number, connected equipment, criticality. A portable label printer produces markings that survive damp and the next ten years, unlike sticky tape scribbled on with a marker pen.

Step 4 — Rank by criticality. Three levels are enough: vital (lift, fire alarm), business-critical (laboratory fax, card terminal), convenience (gate). Deal with them in that order.

Step 5 — Write the shutdown date next to each line. If your operator won't give it to you in writing, chase them by email: this date drives your entire schedule.

Record the results in a shared spreadsheet and, while you're at it, in a technical operations binder kept in the same place as the contracts. On the day of the cut-off, the person who answers the phone is never the person who did the inventory.

A realistic six-month timeline

Switching over a fax isn't a heavy IT project, but it comes with a constraint of its own: your correspondents need to know your new number, or you need to keep the old one. This question of number porting drives everything else.

D-180 — Decide the fate of the number. If your fax number is printed on prescriptions, letterheads, professional directories or has been declared to a public authority, you need to port it to your online fax provider. Porting a geographic number to a dematerialised fax service is routine, but it requires a signed mandate, a RIO code and two to six weeks of processing. It's the longest item on the list: start with it.

D-120 — Choose the provider. Non-negotiable criteria for professional use in France: data hosted within the European Union, encryption in transit and at rest, transmission logs with timestamped receipts, configurable retention periods and — for healthcare professions — the ability to document GDPR compliance and, where applicable, compliance with the health data hosting framework. We go into detail on these points in our guide to sending a fax online.

D-90 — Run both channels in parallel. For one month, send via both channels to your ten most frequent correspondents. Compare the receipts. This is where you'll discover that the court registry won't accept automatically generated headers, or that the laboratory rejects PDFs larger than 5 MB.

D-60 — Notify your correspondents. A standard letter or email, with the old and new numbers, the switchover date and a backup contact. Update your letterheads, your email signature, your directory listings and your legal notices.

D-30 — Freeze changes. Nothing else gets modified during the final month, barring incidents.

D-0 — Switchover and monitoring. Someone is appointed to check every day, for two weeks, that outgoing faxes get through and that incoming ones land in the right inbox.

What changes for the evidential value of your transmissions

Good news: the migration doesn't weaken your legal position — more often than not, it strengthens it.

The transmission report from an analogue fax machine never had any magical value. Before a judge, it is one piece of evidence among others, its weight depending on the context and on the practices established between the parties — a subject we cover in our article on the evidential value of the fax. A serious online fax service, by contrast, produces a complete electronic log: transmission ID, server timestamp, number dialled, page count, status, and often the exact image of the document sent. That's more robust, not less.

Two precautions go with this switchover:

1. Retrieve the history. Many multifunction fax machines store recent transmissions and activity logs in memory. Export them before unplugging, and above all wipe the internal drive before the machine leaves the premises: a decommissioned office copier often contains several thousand pages in the clear. Destruction providers issue a certificate; failing that, secure erasure software and a signed internal record will do the job.
2. Set the retention rules with your provider. An online fax service stores your documents on its servers. Define the retention period, the periodic export to your own archiving system, and what happens to the data at the end of the contract. Our recommendations on long-term retention are set out in the article on archiving faxes.

For organisations that receive sensitive documents, plan for the accumulated paper too: a cross-cut shredder rated P-4 or higher remains the single most useful accessory of this transition, once the receiving trays finally empty out.

Special cases that deserve separate handling

Healthcare professionals. The fax is still used for reports, prescriptions sent to pharmacies and exchanges with hospitals. The migration is an opportunity to move to a secure healthcare messaging system, which offers a far better framework. Online fax can serve as a transition, provided the supplier documents how it processes health data.

Alarms and lifts. Don't handle these yourself. IP alarm transmission requires an approved replacement module and a revised contract with the monitoring centre. An uninterruptible power supply with backup battery becomes essential here: on the PSTN, the line was powered from the exchange and survived power cuts; on IP, if the router goes down, the safety link goes with it.

Poorly served areas. Where fibre isn't available and ADSL is unstable, online fax over a backup 4G/5G connection is often more reliable than a T.38 gateway on a saturated link. A 4G router with a SIM slot set to fail over automatically costs less than half a day of downtime.

Frequently asked questions

How do I know whether my fax line is still on the PSTN?

Check your bill: a PSTN access is billed as an "analogue line" or "main line", distinct from a fibre subscription or a voice-over-IP plan. If in doubt, call customer services with the line number to hand and explicitly ask for the access type and the planned shutdown date for the batch.

Can I keep my fax number after the PSTN shutdown?

Yes, in the vast majority of cases. Porting to an online fax operator preserves your geographic number. Plan ahead: allow several weeks between the porting mandate and the actual switchover, and never cancel the old line before the port is confirmed — cancellation destroys the number.

Does my multifunction fax machine become useless?

No. It loses its fax function but keeps printing, copying and scanning, which are often its main uses anyway. You can also connect it to an online fax service via the "scan to email" function, turning the machine into a simple scanner at the front of the sending chain.

What if a correspondent only accepts paper faxes?

An online fax dials exactly the same number and comes out of exactly the same machine at your correspondent's end: from their point of view, nothing changes. That is precisely the point of the arrangement, and the reason the channel will outlive its historic carrier by a few more years.

Do I need to notify a public authority of my change of number?

Yes, whenever the number appears in a declaration, an approval, a professional body registration or a contract. Do it in writing, keep the acknowledgement, and check that public directories have been updated. The list of destinations covered by our services is on the available countries page.

In summary

• The PSTN shutdown happens in geographic batches with firm dates: ask for yours in writing, don't settle for a year.
• The inventory isn't just about the fax: alarms, lifts, card terminals and remote metering share the same analogue lines.
• Plugging a fax machine into a router without T.38 or the G.711 codec produces random failures: it's the false good idea of the whole exercise.
• Number porting is the longest item: start it six months ahead, and never cancel before confirmation.
• Run both channels in parallel for a month before the switchover, then monitor daily for a fortnight.
• Wipe the memory of the decommissioned copier: it holds your documents in the clear.
• The migration strengthens your audit trail: timestamped logs, exportable receipts, controlled archiving.
• The PSTN will have lasted more than a century. The fax isn't dying with it: it's simply changing pipes. Those who plan ahead won't notice a thing. The others will discover the problem on a Monday morning, with a file to file before midday.