Why Your Card Machine Stops When the Broadband Drops

The Friday night version of this problem

It is half past eight on a Friday. The restaurant is full, there is a queue at the bar, and the card terminal says "connection error". Someone restarts it. Same message. Someone turns the router off and on. Same message. By the time a manager has phoned the broadband provider and sat in a queue, twenty minutes have gone, three tables have left without paying their full bill because they had no cash, and the staff are writing card numbers on a notepad, which is a data protection problem on top of everything else.

We get called into this scene a few times every year, and the numbers are always worse than the owner expected. A busy independent restaurant in Liverpool city centre loses somewhere between £1,500 and £4,000 of takings in a two-hour outage on a Friday service, before you count the cost of the goodwill. One of our customers worked out that a single evening of "cash only, sorry" had cost more than five years of the failover they then asked us to fit.

What is actually breaking

Almost everyone blames the card machine. It is almost never the card machine.

A modern card terminal, whether it is a countertop PDQ or a handheld on the table, is an internet device. It takes the card details, encrypts them, sends them to the acquirer over the internet, waits for an approval, and prints a receipt. No internet, no approval, no sale. The terminal is working perfectly; it simply has nothing to talk to.

So the chain you are actually relying on is: the terminal, the Wi-Fi or cable it uses, your router, the broadband line from the router to the street, and the carrier's network beyond that. When any one of those fails, the symptom is identical: "connection error" on the terminal. The router and the line are by far the most common culprits, and the line is the one you can do least about in the moment.

The same is true of a cloud-based till. It will usually keep taking orders in an offline mode for a while, but reports, stock, kitchen screens on Wi-Fi and the card payments that go through it all depend on the same line.

Why one line is a single point of failure

Most hospitality and retail premises run on a single consumer-grade or "business broadband" line. That is fine until it is not, and three things make it worse than it looks:

• Consumer and entry-level business broadband has no meaningful service level agreement. When it goes down, the provider's target to fix it is typically 24 to 72 hours. For a restaurant that is one to three trading days.
• "We have two routers" is not resilience if both plug into the same line. Neither is a second router on a second line from the same provider over the same street cabinet, because the fault is usually in the cabinet or the exchange, and both lines share it.
• Faults cluster at the worst times. Cabinets are worked on in the evening, storms are in the evening, and the engineer who accidentally disconnects you is on a shift that finishes at five.

A single line is a single point of failure for everything that makes money in the building. Failover is the name for giving it a second way out.

What failover actually is

Failover is a second internet connection, usually 4G or 5G, plugged into a router that is clever enough to notice when the main line has gone and to switch traffic over to the backup automatically, and then to switch back when the line returns.

The word that matters is automatic. We have seen plenty of premises with a 4G dongle in a drawer "for emergencies". It has never been used, because in an emergency nobody remembers it, nobody knows how to set it up, and the staff who are there at nine on a Saturday were not there when it was bought. If the switchover needs a human, it does not happen.

What stays up on a 4G or 5G backup: card payments, the cloud sync for your till, kitchen printers and screens, the phones if they are internet phones, the booking system, the music if you are unlucky enough to rely on streaming. Card authorisations are tiny amounts of data, so they do not notice the difference.

What does not: large uploads, CCTV being viewed remotely at full quality, and anything that was already slow. That is fine. The backup is there to keep the trading going, not to replace the line.

What it costs

Every premises is different, so treat these as ranges rather than quotes, but they are the real ranges we see.

The install for the middle option, which is the one we fit most, is a business router with a built-in or attached 4G or 5G modem, an external antenna where the signal needs it, and an hour of configuration and testing. The one-off cost typically lands in the low hundreds. Against a single lost Friday service, it is not a difficult sum.

When it is worth it, and when it is not

Here is the honest version. A small office that could email tomorrow, and whose phones are mobiles, does not need failover. If the line drops, people go home early. Nothing is lost that cannot be caught up.

Anywhere that takes card payments during fixed trading hours needs it, full stop. Restaurants, bars, cafes, shops, takeaways, salons, anywhere with a queue. The whole point of a trading session is that it cannot be rescheduled. The customer who could not pay at eight on Friday does not come back at ten on Tuesday to settle up.

The same logic applies to a multi-site group, only more so, because an outage at one site is a phone call to head office and a mess in the weekly numbers. On a rollout we put failover in the standard build for every site, so nobody has to decide each time.

What to do this week

If you are reading this after an outage, three things in order. First, find out what actually failed: ask your provider for the fault reference and the cause, because "the line" and "the router" need different fixes. Second, check whether your card terminals use your network or their own SIMs, because that decides how one backup can protect all of them. Third, get a business router with 4G or 5G failover fitted and tested. It is an afternoon's work and it is usually the best-value thing we do for a venue all year. Our business internet and failover page covers the options in more detail, and if the till itself is part of the problem, the EPOS systems page explains how we keep card terminals and tills on one protected network.