Why EFTPOS stops working when the crowd arrives
Most portable terminals connect through mobile data, either with their own SIM or through a paired phone. At a quiet site that works well. When thousands of people gather in one place, they all lean on the same nearby mobile towers to post photos, send messages and find each other. Mobile networks can congest under that load, and each transaction becomes one more request waiting in the queue.
The timing makes it worse. Congestion peaks at exactly the moments you most need payments: gates opening, the interval, the last half hour of a market. A stallholder who tested their terminal at bump-in sees it work, then watches it time out at the busiest moment of the day. The terminal isn't faulty; its connection is.
Ways a payment terminal can connect at an event
How each connection type tends to behave at a busy event. Your payment provider can tell you which options your own terminals support.
| Connection | How it works | At a busy event | What to check |
|---|---|---|---|
| Terminal with its own SIM | Uses mobile data directly | Shares mobile capacity with the crowd | Signal at your stall at a busy time, not at bump-in |
| Terminal paired with a phone or tablet | Relies on the phone's mobile data or WiFi | Depends on the phone's connection, battery and pairing | Whether the phone can join the payment WiFi instead |
| Terminal on WiFi | Joins a WiFi network you choose | As dependable as that network; guest WiFi is the weak point | Which WiFi bands and security settings it supports |
| Terminal or POS on a cable | Plugged into a network switch | The steadiest option where a cable can reach | Whether the equipment has a network port |
Behaviour varies by terminal and provider. Confirm the details with your payment provider rather than assuming.
Temporary EFTPOS for market stalls
Markets put dozens of terminals in long rows, often outdoors, each owned by a different stallholder with a different provider. The organiser can't control the terminals, but can control the network they join. A payment-only WiFi network along the stall rows, with its own name and password handed to stallholders at check-in, takes terminals off the crowded mobile network and away from any public WiFi.
Bandwidth is rarely the issue, because payments use little data. Coverage and capacity are what matter. Count the terminals: 40 stalls with one or two each is 40–80 devices, so at about 50 devices per access point the payment network needs at least two (80 ÷ 50 = 1.6, rounded up). The rows usually decide the final number, since each access point has to reach the stalls at both ends of its stretch. The full market setup is on our market stall WiFi page.
What a dedicated payment network needs
The network side of event EFTPOS WiFi comes down to five things.
Its own WiFi name and VLAN
Only terminals, POS tablets and scanners join it. Guests never see the password and guest devices can't reach payment devices, as explained in separate networks for events.
A reserved share of the connection
Payments get their share at the router, so a busy guest network can't crowd them out at the gates or the bar.
Coverage where terminals actually are
Stall rows, bars, merchandise tents and roaming staff with handheld terminals all need signal, including the far end of each row.
A backup internet path
If the main connection fails, a second one, often a 4G/5G router, keeps payments moving while the main line is restored.
Sensible placement and power
Access points and routers sit away from foot traffic, with power positions agreed with the event's power supplier.
Questions to ask your payment provider before the event
Every provider and terminal differs. Put these to yours, and don't assume another stallholder's answers apply to you.
- Does the terminal connect by SIM, WiFi, a paired phone or a cable?
- Which WiFi bands and security settings does it support?
- Does it have an offline or deferred mode, and how does that work?
- Are there limits on offline transactions, by number or by value?
- When are stored transactions sent, and what happens if any are declined?
- Does the provider recommend a particular network setup for events?
- How should staff take a payment if the terminal can't connect at all?
- Who do we call on the day if terminals stop working?
Testing EFTPOS before doors open
Every terminal, every position, before the first customer. It takes less time than one queue of failed payments.
Join each terminal to the payment network
Do it at bump-in, at the terminal's real position, and confirm it's using the payment WiFi rather than mobile data or the guest network.
Run a small test transaction on every terminal
Not a sample: every one. A working terminal at one end of the row says nothing about the terminal at the other end.
Walk the rows and bars with a terminal
Check the edges of coverage, behind stand walls and inside tents, where signal is weakest.
Test the backup
Switch the payment network to the backup connection and run another transaction, so you know the backup carries payments too.
Brief the people at the terminals
Stallholders and bar staff should know the network name, who to tell about problems, and what to do if a terminal won't connect.
Worked example: bars and merchandise at a 3,000-person concert
Four bars with four terminals each (16), a merchandise tent with six, and ten ticket scanners at the gates make 32 payment and ticketing devices. Add 20 staff at 1.5 devices each (30) and the operational networks carry 62 devices. On capacity alone, 62 ÷ 50 = 1.24, so two access points.
But the bars sit at opposite ends of the site, the tent is near the exit and the gates are out front: four separate zones. Coverage decides, so each zone gets its own access point, plus one more near the busiest bar, five in all. Data use is small and a modest connection carries it. A crowd of 3,000 will congest local mobile networks, which is exactly why the terminals shouldn't depend on them. Gates are covered in more depth in ticket scanning WiFi.
Questions people ask
Why does EFTPOS not work at events?
EFTPOS at events usually fails because terminals depend on mobile data, which can congest when a large crowd gathers, or on guest WiFi shared with everyone. Transactions then time out at the busiest moments. A dedicated payment WiFi network, enough access points along stall rows and bars, and a tested backup connection prevent most of these failures.
Can I use event WiFi for my EFTPOS terminal?
Often, if the terminal supports WiFi and the event provides a payment network. Use the payment network rather than guest WiFi, check with your payment provider which WiFi bands and security settings your terminal supports, and run a test transaction at your stall before doors open. A terminal that only uses its own SIM can't join WiFi.
Do SIM EFTPOS terminals work at festivals?
SIM terminals work at festivals when the local mobile network has capacity to spare, but mobile networks can congest when thousands of people gather, so transactions may slow or fail at peak times. Check whether your terminal can also use WiFi, ask the organiser about a payment network, and ask your payment provider about offline or backup options.
What happens to EFTPOS if the internet goes down?
It depends on the terminal and the payment provider. Some terminals can store transactions offline for a time, within limits, while others stop accepting cards until they reconnect. Ask your payment provider exactly how your terminals behave and what the limits are. A backup internet connection on the payment network reduces how often you need to find out.
How much internet do EFTPOS terminals need?
Very little. EFTPOS terminals send small amounts of data per transaction, so bandwidth is rarely the problem. What they need is a connection that stays up at the busiest moment, coverage at every stall or bar, and a network not shared with guests. Count terminals as devices when working out access points, at about 50 per access point.
How do market organisers provide EFTPOS WiFi for stallholders?
Organisers set up a payment-only WiFi network along the stall rows, with its own name and password given to stallholders at check-in and kept separate from any public WiFi. Access points are placed to reach both ends of each row, a backup connection covers outages, and stallholders test their terminals on the network before the market opens.
Sources
Planning figures on this page are starting points. Every network is confirmed against the actual site.
