Who tells you the shop's line is down and you cannot take payment?
In short
When the line drops, a card terminal keeps accepting: it stores the payment and forwards it later, so the failure is invisible at the counter and becomes visible days afterwards, in the reconciliation. The line, the terminal, the certificate and the time are all watchable. What the payment did at the bank is not.
The story that gets told in the trade is always the same shape. It is the end of dinner, or the end of the queue, and someone has to ask the customer whether they would mind writing their card number on a piece of paper. Whatever happened technically, that is the moment the failure becomes a business problem — and it is almost always the first moment anyone knew.
Why does nobody notice at the counter?
Because the equipment is designed not to make a scene. A card terminal that cannot reach the acquirer is generally built to keep taking payments: it stores them and forwards them when the line returns. That is a sensible design — it keeps the shop trading through a five-minute outage — and it is exactly why an hour-long outage is invisible until it is expensive.
Two things then happen out of sight. The stored transactions are not authorisations: some of them can come back refused, days later, when the customer is gone. And the store has a ceiling; once it is reached, the terminal really does stop, usually at the worst possible moment.
Meanwhile the till still prints, the screen still lights up, and nothing anywhere says the word “offline” loudly enough for a busy counter to hear it.
What can you watch, and what does each check prove?
- The line itself, from outside and from inside. From outside you learn that the shop is unreachable; from inside, a small probe on the shop’s network tells you whether it is the whole line or one device that has gone. Those are different problems with different phone calls.
- The payment gateway and the till, as things that must answer: reachable, on the expected port, within the expected time.
- The certificates, with the days counted down. This is the failure that is fully preventable and still happens every year: a device that worked all week refuses to start on Saturday because a certificate expired overnight. Warnings should start weeks out and get louder — a message, then a call — and they should keep coming every day once the date has passed.
- The clock. A terminal or till whose time has drifted puts the wrong time on every receipt it prints, which is nobody’s emergency until the day someone has to match a transaction to a camera or a dispute.
- The address the shop reaches the internet from. When it changes, something changed: usually the main line dropped and the backup took over. Trading continues, quietly, on a connection that may be slower and metered — and that is worth knowing on the day, not on the invoice.
When the line dies, who is left to tell you?
This is the honest catch of watching from inside. A probe sitting on the shop’s network cannot report that the shop’s network is down — it has no way out. Two things have to cover for it.
First, the platform must notice the silence: a probe that stops reporting is itself an alert, and that is what turns “we hear nothing” into “the shop is offline”. Second, the probe must not lose the minutes it spent alone: its results should be kept locally while the link is gone and replayed when it returns, so the history of the outage survives and you can see exactly when it started rather than guessing.
What to do this week
- Decide who gets the call. One name, the person who opens the shop, and a real phone call rather than an email.
- Watch the line from both sides — from outside the shop, and from a probe inside it — so you can tell an outage from a broken device.
- Put the certificates of the payment devices and the till on a countdown. That one is free money.
- Check the time on the till and the terminal against a reliable clock. Write down what you found.
- If there is a backup connection, make sure the switch to it is something you are told about, not something you discover.
Nobody remembers the outage you fixed in twelve minutes. Everybody remembers being asked to write their card number on a piece of paper.
What we cannot tell you
- We cannot tell you that a payment was settled: what happens between the terminal and the bank is outside anything we can reach, and we will not imply otherwise.
- We cannot see how many stored transactions are waiting inside a terminal, or what the end-of-day batch did with them: no standard publishes that.
- We cannot see the card reader itself, only whether the things it depends on — the line, the gateway, the till, the certificate — are answering.
- We cannot fix a dead line: we tell you it is dead, which minute it died, and whether it is the line or only one device on it.
Questions people actually ask
If the line drops, does the terminal stop working?
Usually not, and that is the difficulty. Card terminals are built to survive a dropped line: they store the transaction and forward it when the connection comes back. At the counter everything looks normal. The problem surfaces later, when some of those stored payments come back declined and the card is long gone.
So how is the shop supposed to notice?
Not from the till, which is behaving exactly as designed. From outside it: something that checks the line and the payment gateway every minute and says so the moment the answer changes. In a shop the useful alert is not an email — it is a message on a phone that is already in someone's hand.
What actually breaks on a Saturday?
Three things, in this order: the internet line, which is the loud one; an expired certificate, which stops a device dead at the next restart and is announced weeks in advance to anyone counting the days; and the clock, which quietly puts the wrong time on receipts and makes the day's records hard to reconcile.
We have a backup connection. Is that enough?
It is enough to keep trading, not enough to know. A shop that has silently fallen back to mobile data works more slowly, sometimes costs more, and nobody notices until the bill arrives. When the public address a shop reaches the internet from changes, that is visible — and it is usually the first sign the main line has gone.
Who should be woken up, and how?
For a shop, the honest list is short: the person who opens up. A phone call is the only channel that does not depend on someone looking at a screen, and it should respect the hours the shop is closed. Everything else — chat message, email — is for the record and for the morning.