The Last-Mile Trap: The Devices Risking Your PSTN Switch-Off Readiness

Enterprises are migrating their PBX systems successfully, but failing on the forgotten endpoints that are left unaccounted or budgeted for.

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The Last-Mile Trap: The Devices Risking Your PSTN Switch-Off Readiness
Security, Compliance & RiskFeature

Published: February 12, 2026

Kristian McCann

Across Europe and North America, telecommunications providers are dismantling the infrastructure that has carried enterprise voice traffic for over a century. The transition from analog copper networks to all-IP connectivity is accelerating. Some European markets face mandatory cutoffs in 2025, while the UK has set a hard 2027 deadline. The US rollout is more fragmented, with retirement schedules varying by region and carrier, but the direction is clear and irreversible.

For most enterprises, the instinctive response focuses on the obvious: migrate the PBX, upgrade desk phones, and transition to UCaaS platforms. These are substantial projects, certainly, but they are also well-understood challenges with established solution patterns. The real migration failures happen elsewhere, in the inventory blind spots where analog connectivity has quietly proliferated far beyond traditional telephony.

For those managing their migrations, Ryan Zoehner, CEO at Algo, argues that recognizing the full extent of the sprawl is essential.

“Organizations really need to understand that there’s this mistaken belief that the switch-off only impacts traditional phones, desk lines, landlines, and voice services.”

This perception gap is creating a dangerous vulnerability.

While IT departments methodically work through PBX replacements and VoIP rollouts, they are often unaware of the dozens, sometimes hundreds, of other devices depending on the same copper circuits. Devices nobody knows exist until the copper lines start going dark and critical equipment stops working.

Why the Last 10% Takes Longer Than the First 90%

For decades, PSTN infrastructure has been the universal connectivity standard, a reliable, always-on network that required minimal configuration and just worked. “This is a fundamental piece of technology bedrock that underpins far more than just voice,” Zoehner explains. That reliability made it the default choice for any device.

The problem is that this proliferation happened organically, over years, across organizational silos. A security contractor installs a fire panel with a monitoring line in 2008. Facilities add elevator emergency phones during a building refurbishment in 2012. Retail operations roll out payment terminals with analog backup lines in 2015. Each decision made sense individually, but collectively they have created an undocumented web of analog dependencies that most organizations cannot accurately map.

Attempting line-level discovery quickly reveals why this is harder than it sounds. Carrier billing systems list circuit IDs and monthly charges but rarely describe what each line actually connects to. Telecom expense management platforms can track spending trends but cannot tell you whether a circuit serves a phone or a critical building system. Site documentation, if it exists at all, is often outdated, stored across multiple systems, or held by third-party facilities management companies. The challenge intensifies at remote locations and leased premises where documentation practices may be inconsistent or entirely absent.

Ownership fragmentation compounds the challenge exponentially. Desk phones belong to IT. The fire alarm reports to health and safety. Payment terminals are managed by finance or retail operations. Building access systems fall under physical security or facilities. Emergency communications might sit with property management or with the landlord in leased locations.

No single department has complete visibility, which means no single team can drive a complete and accurate migration.

From Discovery to Deployment: What Actually Works

The organizations navigating this successfully are not starting with solutions. They are starting with visibility. The first step is always a comprehensive discovery exercise that goes well beyond pulling carrier bills or checking asset management databases. It requires physical site visits, conversations with facilities teams, and systematic checks of every location where analog connectivity might be hiding.

This discovery work needs to capture not just “what exists” but “what it does.” A fire alarm panel is not merely a device on line 347. It is a life-safety system with regulatory compliance requirements and specific response protocols. Understanding these functional requirements is essential for selecting appropriate replacements. Some systems can tolerate brief connectivity interruptions; others cannot. These nuances determine whether a simple adapter will suffice or whether the entire system needs replacement.

Once organizations have mapped their analog footprint, replacement patterns start to emerge. For many devices, the goal is not to upgrade the endpoint itself but to shift its connectivity off the copper network. Modern analog terminal adapters and cellular bridges make this remarkably straightforward for compatible equipment.

“It’s just converting the old analog device to run on cellular. You just take the copper line out and plug in the box,”

explains Lathan Lewis, Head of Products at Tango Networks.

This approach preserves existing devices and avoids the cost and disruption of wholesale replacement, while moving them to connectivity that will survive the copper switch-off. The fire panel still triggers the same monitoring center, and the elevator phone still connects to emergency services, but the path it takes no longer depends on infrastructure scheduled for decommissioning.

For organizations willing to invest in full IP-native replacements, the opportunity extends beyond maintaining current functionality. Modern IP endpoints integrate directly with UCaaS platforms, enabling capabilities that analog systems never offered.

“UCaaS can provide insights into call volumes, response times, communication costs, and even caller sentiment,”

notes Paul Holden, VP of EMEA Sales at CallTower. “Managers can then use this data to make smarter decisions, optimize staffing, or identify trends in their customers’ behavior.” What was once isolated analog infrastructure becomes part of an integrated communications platform enriched with analytics and intelligence that were never possible in the copper era.

Why This Can’t Be Just an IT Project

The single biggest predictor of migration success is not technology choice. It is organizational structure. Enterprises that treat PSTN retirement solely as an IT initiative consistently underperform compared to those that establish cross-functional ownership from the start.

This means bringing together stakeholders who do not typically collaborate on technology projects. IT leads on telephony infrastructure, but facilities managers control building systems. Security teams own access control. Finance manages payment terminals. Property services handle lifts and emergency communications. Each function holds pieces of the analog puzzle, and none can complete it alone.

The most effective approach establishes a dedicated migration team with representation from each affected function. Early workshops focus on discovery, bringing together disparate knowledge to build the first complete inventory. Site visits follow, with cross-functional participation ensuring nothing gets missed. Prioritization requires balancing technical feasibility against business criticality, regulatory deadlines, and budget constraints.

Budget conversations become particularly important here. Capital expenditure for new building systems typically sits outside IT budgets. Ongoing costs for cellular connectivity need finance approval. Without coordinated budget planning, projects stall even when the technical path is clear.

Testing and validation form the final critical workstream. IT can verify that an IP endpoint connects to the network, but only facilities can confirm that a fire alarm still triggers correct evacuation procedures. This validation often reveals integration issues requiring additional remediation.

Why Organizational Structure Matters More Than Technology

PSTN retirement feels like a deadline-driven compliance exercise, but the enterprises struggling most are not those with complex technical estates. They are those that treated this as purely an IT project. By the time they discovered their forgotten fire panels and payment terminals, the window for strategic planning had closed.

The single biggest differentiator between migration success and failure is organizational structure. IT cannot execute this alone because the devices that need migrating do not report to IT. Facilities managers control building systems. Security teams own access control. Finance manages payment terminals. Property services handle emergency communications. Each function holds pieces of the analog puzzle, and none can complete it alone.

Organizations approaching PSTN retirement holistically are deploying integrated IP communications platforms that deliver capabilities their legacy analog infrastructure never could. They are not just maintaining current functionality. They are modernizing their entire communications estate while they have organizational attention and budget allocated.

Those who delay will eventually complete the migration. Copper retirement leaves no alternative. But they will do so reactively, under deadline pressure, with far less control over outcomes and costs.

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