1.1. Achieving 24 Hours of Operation with a Single Battery

As the retirement of traditional POTS networks accelerates, the need for reliable, self-sustaining voice devices has become more urgent. In emergency and distributed deployments—such as elevators, fire panels, and building security systems—continuity of service is paramount. Vola Networks’ PR12 introduces TRU24™ Standby Technology, a proprietary low-power design that enables up to 26 hours of standby time using only a single compact rechargeable battery. This paper explains the engineering principles behind TRU24™, the operational modes of PR12, and why its low-power standby model sets a new standard in the industry.

PR12

1.2. Battery Efficiency by Design

Unlike typical VoIP gateways that rely heavily on constant DC input, the PR12 was engineered to function autonomously for extended periods when disconnected from DC power. At the core of this design is a lithium-ion cell with carefully managed charge/discharge thresholds.

This optimized voltage window balances capacity utilization, cycle life, and safety compliance (meeting UL62368-1 standards). Combined with highly efficient power regulation circuitry, the PR12 minimizes wasted energy and maximizes usable runtime from a small form-factor cell.

1.3. Low-Power Standby Architecture

TRU24™ standby is not achieved through battery capacity alone; it is enabled by system-level power management:

Sleep Mode on DC Disconnect

Once external DC power is removed, PR12 automatically transitions into sleep mode.

In this mode, high-consumption components such as WAN and LAN Ethernet ports are powered down.

Periodic Wake Cycles

During standby, the system wakes approximately every 30 seconds to perform minimal status checks.

This design ensures the device remains responsive without drawing constant current.

Optimized Cloud Connectivity

VolaCloud maintains a heartbeat interval of 300 seconds (5 minutes).

The PR12 synchronizes its wake cycle with this interval, allowing efficient connectivity and remote status monitoring while conserving energy.

Event-Triggered Wake

Incoming SIP or VoLTE signaling immediately wakes the PR12 to full operation.

This ensures no missed calls or alarms during standby, making it suitable for mission-critical deployments.

1.4. Real-World Testing Results

Internal laboratory validation demonstrates that PR12’s standby operation reaches 26 hours under optimized conditions. Key parameters of the test:

Device powered only by its internal battery.

Connected to two analog phones.

PR12 left in sleep/standby mode, waking as per defined cycles.

The testing confirmed that even under these constrained conditions, the device sustained continuous readiness for over a full day. Importantly, actual field performance may vary depending on attached analog endpoints, as phones with displays or high on-hook current will reduce standby time.

1.5. User Experience in Standby

From an operational standpoint, standby mode is seamless:

Reconnection: When external DC is reapplied, Ethernet ports are automatically re-enabled, restoring full routing and LAN/WAN capability.

Service Continuity: Even in battery-only mode, the PR12 remains responsive to VoIP or VoLTE calls, ensuring uninterrupted emergency service.

Cloud Visibility: VolaCloud continues to report essential metrics—including battery status—at its 300-second interval, giving administrators confidence in remote deployments.

1.6. Why One Small Battery is Enough

Competing devices often require large battery packs or external UPS systems to achieve similar runtime. PR12’s innovation lies in its low-power architecture, not oversized cells. By reducing idle consumption, PR12 makes it possible to deliver full-day autonomy with a compact, field-replaceable battery module.

This has three advantages for customers:

Smaller Device Footprint – Easier installation in confined spaces such as elevator control rooms.

Lower Maintenance Costs – Batteries are easier and cheaper to replace in the field.

Regulatory Compliance – The compact battery design simplifies logistics while meeting international safety certifications.

1.7. Implications for MSPs and Enterprises

For Managed Service Providers (MSPs), TRU24™ translates directly into operational reliability at scale:

Reduced truck rolls – Remote monitoring ensures MSPs can track battery health and runtime through VolaCloud.

Regulatory readiness – PR12 meets compliance standards for carriers, federal procurement, and safety.

Customer trust – Ensures that emergency lines, alarms, and elevator phones stay operational even during power outages.

Conclusion

The PR12 with TRU24™ Standby Technology redefines what is possible with a single compact battery. Through careful power management, periodic wake cycles, and efficient cloud synchronization, the device achieves up to 26 hours of standby time without external DC input. Its field-replaceable battery, compliance with safety standards, and seamless responsiveness to SIP and VoLTE calls make it a unique solution in the market.

For customers facing the sunset of copper POTS lines, PR12 offers a future-proof, energy-efficient, and reliable alternative, ensuring that critical communications remain uninterrupted in every scenario.

PR12