By Katherine Beaty

During the past year, I’ve seen the same issue surface in two very different, but equally demanding, environments: one of the most significant airport valet operations in the country and one of the most extensive beach parking operations in the U.S. Different geographies, different operators, different hardware. The common thread was cellular devices with multiple subscriber identity module (multi-SIM) cards configured for automatic or random carrier selection and the quiet chaos that followed.

Multi-SIM technology is often marketed as a form of redundancy. In practice, when misunderstood or poorly configured, it can introduce instability at the exact moment reliability matters most: during real-time payment processing over cellular networks.

What the failures actually look like

These situations didn’t involve abstract “connectivity challenges.” They showed up as real operational and financial failures:

• Duplicate payments

• Lost transactions

• Transactions that became “stuck” mid-process

• Devices unable to connect to any carrier

• Excessive time, sometimes three to five minutes, to establish a usable connection

At an airport valet operation handling enormous daily volume, a three-to-five-minute connection delay is not a nuisance. It is operational damage. Customers are waiting at the curb. Lines back up. Attendants retry transactions. The customer experience deteriorates fast.

In large beach parking operations, the impact showed up differently but was just as serious. Intermittent connectivity and delayed transactions greatly complicated efforts to reconcile cash totals. Attendants ended shifts with unexplained overages and shortages. When transaction data is unreliable, operators lose visibility, and when visibility disappears, distinguishing system failure from human behavior becomes nearly impossible. That’s not just inconvenient; it’s risk exposure.

The core misunderstanding

At the heart of this issue is a fundamental misconception:

Many assume that if multi-SIM works well for talk and text, it will work the same way for payment processing. It does not.

Voice and text communications are forgiving. Payments are not.

Dropped calls are annoying. Dropped or delayed payment sessions create financial ambiguity. Payment processing depends on stable sessions, predictable routing, and timely acknowledgments. When a device silently switches carriers mid-process, or aggressively hunts for the “best” signal, those assumptions
break down.

Multi-SIM devices configured for random or automatic selection may optimize for signal strength, but payments don’t care about bars on a screen. They care about consistency.

Airports, beaches, and reality

In the airport environment, devices configured for automatic SIM switching routinely took several minutes to attach to a network and begin processing transactions. Stabilizing those devices to a specific carrier significantly reduced failures, not because that carrier was perfect, but because consistency mattered more than theoretical redundancy.

At the beach, a similar stabilization approach helped reduce transaction anomalies and reconciliation issues, but it didn’t eliminate them. And that matters, because it highlights an uncomfortable truth: Cellular networks are shared infrastructure. During peak travel periods, major events, or heavy tourist traffic, bandwidth degradation affects every carrier. Multi-SIM does not magically solve congestion.

Operators shouldn’t need a Ph.D.

Let’s be clear about something: Parking operators did not enter this industry expecting to become experts on cellular networks.

They should not need an engineering degree to understand SIM selection logic, carrier attach times, bandwidth saturation, or session persistence just to run a reliable payment operation. 

Yet increasingly, they are forced to learn these details because they’re hidden behind oversimplified promises of “automatic redundancy” and “seamless connectivity.”

When a system only works reliably if operators become telecom specialists, the problem is not operator education. It’s how technology is being positioned, configured, and deployed.

Coverage is not reliability

The parking industry has quietly conflated coverage with reliability. They are not the same.

For payment processing, reliability means:

• Predictable behavior

• Stable network sessions

• Controlled failover, not constant switching

• Known failure modes, not random ones

Multi-SIM can absolutely be useful when deployed deliberately, with clear rules around when and how switching occurs. But blind automation, especially in transaction-critical environments, creates more problems than it solves.

Questions operators should ask

Operators typically ask, “How many SIMs does this device support?” Instead, they should ask the following:

• How does the device decide which SIM to use?

• When does it switch carriers, and what triggers that switch?

• What happens to an in-flight transaction during a carrier change?

• Can SIMs be pinned or prioritized by environment?

• How does the system behave under congestion, and not just low signal?

These are not edge cases. They are daily realities in high-volume parking operations.

Final thought

Multi-SIM technology isn’t inherently bad. But the way it’s sold as a simple, automatic fix for connectivity is misleading. In payment environments, predictability beats optionality. Stability beats “best signal.” And clarity beats marketing.

Parking operators shouldn’t need to become cellular engineers to protect revenue, maintain accountability, and deliver a good customer experience. If the industry wants to scale reliably, it’s time to stop pretending that more SIMs automatically mean better outcomes.

KATHERINE BEATY is the CEO and president of Beaty Solutions. She can be reached at [email protected].