What Is Cellular Failover?
Cellular failover is the automatic re-routing of network traffic from a wired internet connection (cable, fiber, DSL) to a 4G LTE or 5G cellular link when the primary connection fails. A failover router monitors the wired uplink continuously and, on detecting an outage, switches outbound traffic to its built-in cellular modem within seconds. When the wired link recovers, the router automatically reverts.
Why does POS need cellular failover?
Card payment networks (Visa, Mastercard, AMEX) impose a strict transaction timeout — typically 30 seconds. If the wired internet drops while a payment is mid-flight, the transaction fails. The customer either retries (annoying) or walks (revenue lost). For a single-store retailer, that’s a bad day; for a 2,000-store chain, it’s a recurring revenue leak.
Cellular failover solves this by routing the next transaction over LTE/5G the moment the wired link drops. From the POS terminal’s perspective, nothing changed.
The math is hard to ignore. With an average ticket of $35 and 4 transactions per minute at a quick-service restaurant, a 1-hour wired outage costs $8,400 in lost revenue — even before factoring in customer churn. A $40/month cellular failover plan pays for itself the first time it triggers.
How does cellular failover work?
There are three components:
- A failover-capable router — a single device with both a WAN port (for the wired uplink) and a built-in cellular modem.
- An active cellular plan — connected to one or more carriers via SIM card or eSIM.
- Failover detection logic — software running on the router that pings a target (typically Google or a custom endpoint), and on detecting consecutive timeouts, marks the wired link “down” and re-routes traffic over cellular.
Detection is the place vendors differentiate. Slow logic (>30 seconds) means transactions still time out; fast logic (under 4 seconds) means the failover is invisible to users.
How fast should failover happen?
For PCI-DSS-compliant POS environments, failover must complete before the card-network 30-second transaction timeout. Pronto’s PC61-C4G performs failover in under 4 seconds; Cradlepoint’s documented best-case is 8–15 seconds; Cisco Meraki’s native failover (which requires their cellular module add-on) is 10–20 seconds.
Cellular failover vs SD-WAN: what’s the difference?
SD-WAN is a broader software-defined networking category. It can include cellular failover, but its core job is policy-based routing across multiple WAN links (e.g., MPLS + broadband + cellular). For a single-location coffee shop, SD-WAN is overkill. They need failover, not orchestration.
For multi-site enterprises (50+ locations), SD-WAN can layer on top of cellular failover to add traffic-shaping and zero-trust segmentation. But the failover capability itself is foundational.
Cellular failover comparison: how vendors differ
| Capability | Pronto Networks | Cradlepoint | Cisco Meraki | Inseego |
|---|---|---|---|---|
| Failover detection time | < 4 seconds | 8–15 sec | 10–20 sec | 5–10 sec |
| Multi-carrier eSIM (no physical SIM swap) | Yes | No (eSIM as add-on) | No | Limited |
| Cloud management cost | $0 / lifetime | $120–360 / device / yr | $150–200 / AP / yr | $80–200 / device / yr |
| WiFi 6 + cellular in one box | Yes (PC61-C4G) | Separate units | Separate units | Yes |
| Private-label dashboard | Yes | No | No | No |
| Time to deploy a new site | < 10 minutes | 30–60 min | 30–60 min | 20–40 min |
Key Takeaways
- Cellular failover is the automatic re-routing of network traffic from a wired internet connection to a 4G LTE or 5G cellular link when the primary connection fails.
- For point-of-sale (POS), kiosks, ATMs, and digital signage, failover is the difference between continuous revenue and a “system down” sign on the door.
- Modern failover routers switch in under 4 seconds — fast enough that card-payment transactions don’t time out.
- A multi-carrier eSIM router automatically picks the strongest carrier signal (AT&T, T-Mobile, Verizon) at each location, so a regional carrier outage doesn’t take you offline.
- Pronto Networks customers like Toast kept 340 restaurant locations online during a 2024 Comcast regional outage — purely on cellular failover.
FAQs
Is cellular failover the same as a backup internet line?
Not quite. A backup line is a manual switchover (often physical) that someone has to flip. Cellular failover is automatic — it happens within seconds with no human in the loop.
Do I need a separate SIM card or carrier contract?
With Pronto’s multi-carrier eSIM, no. The eSIM ships activated, includes bundled data, and lets the router pick the best carrier at the location. With Cradlepoint or Sierra Wireless, you typically negotiate the carrier contract separately.
Will my POS terminals notice the failover?
On a properly configured network, no. The IP address and gateway behind the failover router stay the same; only the upstream link changes. From the POS terminal’s view, the network never went down.
How much data does failover use?
In failover mode (i.e., wired link is down), POS terminals consume roughly 5–20 MB per terminal per hour. A multi-terminal restaurant during a 1-hour outage uses well under 100 MB — comfortably inside any modern data plan.
What happens during a regional cellular outage?
A multi-carrier eSIM auto-switches to a different carrier (e.g., from T-Mobile to Verizon). A single-carrier failover router would go offline if its carrier was the one having the outage, which is why multi-carrier eSIM matters.
Is cellular failover PCI-DSS compliant?
The cellular link itself is encrypted at the carrier level, but for PCI-DSS compliance, the router must enforce VLAN segmentation, encrypted management, and audit logging. Pronto routers ship with PCI-DSS-aligned defaults; verify with your QSA.
Can I deploy cellular failover at scale (1,000+ sites)?
Yes. Pronto’s REST API + zero-touch provisioning let Toast deploy 50–100 new restaurant sites per week with no manual networking steps. The PC61-C4G ships pre-configured to a customer template; powering it on at the destination is the only on-site step.