Card machine connectivity costs: SIMs, broadband and backup
Budget for a connection that supports trading, including the network behind the terminal and a workable plan for interruptions.
The short answer
Connectivity costs can include terminal SIMs, mobile data, business broadband, routers and backup connections. Check what is already bundled, which devices can use each connection and what happens during failure. A second connection only helps if the payment setup can actually use it when required.
In this guide
Separate terminal data from the wider network
A card-machine SIM may serve only that terminal. It does not necessarily provide internet access for the till, cloud reporting, kitchen displays or online orders. A reader paired with a phone may instead depend on the phone’s data plan, battery and supported app.
Map the path from checkout to payment authorisation. Record Wi-Fi access points, routers, broadband, mobile networks and any managed networking service. This helps identify what a quote includes and where a single failure could interrupt several devices.
Check the recurring and one-off charges
| Item | Question for the supplier |
|---|---|
| Terminal SIM | Is data included in rental, separately billed or subject to a fair-use allowance? |
| Mobile data | What are the allowance, overage and roaming rules? Is use restricted to an approved device or location? |
| Broadband | What installation, router, monthly and contractual costs apply? |
| Backup connection | Is a standby SIM billed even when unused? What happens during activation or heavy use? |
| Network services | Are access points, monitoring, configuration or a VPN required and separately charged? |
| Change or exit | What notice, equipment returns or remaining payments apply? |
Do not assume a terminal can be used abroad because its SIM mentions roaming. Confirm payment-provider permission, device support and the permitted territory separately. Add a VPN only when the approved system design needs it; it is not a universal payment requirement.
Worked example: the extra monthly budget
Fictional arrangement. Two terminal SIMs cost £7 each per month. A backup data plan costs £15 monthly, with a £120 router purchased at setup.
Added recurring cost is £29 monthly or £348 annually. The first year costs £468 including the router.
The business already pays £45 monthly for broadband and would retain it under either payment option. That £540 annual bill belongs in its wider connectivity budget, but is not a £540 saving from switching the terminal supplier.
If one proposal requires a new broadband upgrade, count the additional cost of that upgrade in the comparison. If the existing line can be cancelled, show the actual avoided charge and any exit cost.
Check coverage and test the backup path
Check indoor coverage where payments occur, including the terrace, storeroom, event pitch or upstairs rooms. A postcode coverage estimate is a useful starting point, not proof of reliable service at a particular till.
Ask whether failover is automatic, how long it takes and whether the POS and payment device reconnect without manual changes. Two connections may still share power, equipment or upstream infrastructure. Record those dependencies.
Ofcom advises businesses to compare connectivity service levels and resilience options as well as price. Ask for the repair commitment and exclusions in writing. Run a controlled failover test with the supplier, outside busy trading, and record what still works.
Offline payment acceptance needs its own checks
Offline mode and a live backup connection are different arrangements. Offline acceptance may defer processing and carry later decline risk. Square’s UK guidance, for example, limits supported devices and payment types and places responsibility for expired, declined or disputed offline payments on the merchant.
Confirm the current rules for your exact setup, including upload deadlines, limits, refunds and order routing. Do not assume a kiosk or phone-based acceptance app supports the same offline functions as another device from the same supplier.
Compare the cost with the trading risk
List the extra recurring connection charges and equipment separately from the losses you think they might prevent. A backup connection can be worthwhile without producing a guaranteed saving.
Use the downtime guide to estimate exposure and the TCO checklist to keep connectivity within the complete budget. Enter confirmed recurring fees in the calculator only once, retaining the itemised schedule.
Common questions
Does a mobile card machine need broadband?
Some standalone terminals can use mobile data, while other setups depend on Wi-Fi or a paired phone. Your EPOS software and connected services may still need their own connection.
Is backup broadband the same as offline mode?
No. A working backup maintains connectivity. Offline mode may store payments for later processing, with provider-specific restrictions and risks.
Bring your costs into one clear comparison.
Use the free calculator for your payment fees and supported fixed costs. Keep the wider operating budget alongside it, or ask for a free initial review of an unclear charge or quotation.
No registration required to use the calculator.
Sources and how to use this guide
Primary references checked on 15 October 2026:
- Ofcom: choosing business connectivity and service levels
- Square UK: offline payment support and risks
Worked examples are fictional planning scenarios, not provider quotations, market averages or customer results. They use the costs and assumptions stated, on a consistent VAT basis. Confirm current prices, eligibility and terms in writing.
Read the calculator method and limitations or about EPOS Savings. Source links do not imply a partnership or product endorsement.