How Manufacturers Are Navigating POTS Replacement Across Multi-Site Operations

Estimated reading time: 11 minutes

Manufacturing organizations are among the most operationally complex environments for POTS replacement. A typical manufacturer does not have one facility with a handful of lines. It has plants, warehouses, distribution centers, and administrative offices spread across dozens of states, each with its own mix of fire alarm panels, elevator phones, industrial equipment, and legacy systems that have run reliably on copper for decades.

When carriers start retiring those lines, the pressure lands on facilities, operations, and compliance teams that are already stretched managing production systems, and the consequences of getting it wrong extend beyond telecom. A fire alarm panel that loses its communication path in a manufacturing facility is a safety issue, a regulatory issue, and a potential production shutdown risk all at once.

This post covers what manufacturers need to know about POTS replacement: what their lines are actually connected to, which regulations govern them, why the multi-site nature of manufacturing operations requires a program-level approach, and what a well-executed transition looks like.

What Manufacturing Facilities Use POTS Lines For

Manufacturing facilities typically have a broader and more varied mix of POTS-connected devices than most other business types. Many of these connections were installed as part of building construction or equipment commissioning and have not been actively reviewed since.

• Fire alarm and suppression systems. Every manufacturing facility has fire protection infrastructure. In environments handling flammable materials, heavy machinery, or chemical processes, fire protection is especially critical. NFPA 72 requires compliant communication paths for alarm monitoring, and most panels installed before 2015 rely on POTS lines to meet that requirement. Disconnection of these lines without a compliant replacement creates immediate regulatory exposure.
• Elevator and lift emergency phones. Manufacturing facilities with multi-story buildings, material handling elevators, and personnel lifts are subject to ASME A17.1 emergency communication requirements. Each elevator cab requires a working two-way communication system, most of which are wired to POTS lines.
• Industrial modems and SCADA systems. This is where manufacturing diverges most significantly from other industries. Older programmable logic controllers (PLCs), SCADA systems, and building management systems often include built-in dial-up modems that use POTS lines for remote diagnostics, configuration updates, and alarm reporting. These connections are frequently invisible to facilities and compliance teams because they were commissioned by OEM technicians and documented only in equipment manuals that may no longer be on hand.
• Gate dialers and perimeter security. Manufacturing campuses with controlled-access gates, loading dock intercoms, and perimeter security systems commonly use POTS lines as the communication path for entry authorization and security alerts.
• Fax machines and document transmission. Purchasing departments, quality control teams, and compliance functions in manufacturing still rely heavily on fax for purchase orders, certificates of conformance, regulatory documentation, and supplier communications. Fax use in manufacturing is higher than most facilities and compliance teams assume.
• Blue light and emergency call stations. Large plant floors and outdoor manufacturing campuses often have emergency call stations that connect directly to security or a central monitoring point via POTS lines.
• Point-of-sale and time and attendance systems. Manufacturing facilities with cafeterias, vending operations, and time-clock infrastructure may have POTS-connected devices embedded in those systems.
• T1 and PRI lines at legacy PBX systems. Many manufacturing sites operate legacy PBX phone systems connected via T1 or PRI copper lines. These are subject to the same carrier retirement timelines as POTS lines and require their own T1/PRI replacement strategy.

The Multi-Site Challenge

For a manufacturer with 20 or 200 facilities, the POTS replacement challenge is not primarily technical. It is operational and organizational.

• Inconsistent inventory. In a company that has grown through acquisition or expansion over decades, individual facilities may have entirely different phone systems, alarm vendors, and equipment configurations. There is rarely a centralized record of how many POTS lines exist across the portfolio or what each one is connected to. The actual line count at an enterprise manufacturer almost always exceeds initial estimates once a proper audit is conducted.
• Distributed accountability. At many manufacturers, responsibility for telecom lines sits with corporate IT, while accountability for fire alarm and life-safety systems sits with Facilities or EHS. Neither team has complete visibility into what the other is managing. POTS lines fall through the gap between those organizational boundaries with regularity. When a disconnection notice arrives, it is rarely obvious whose problem it is. The answer is that it belongs with Facilities and EHS, because the consequences are compliance and safety, not connectivity.
• Remote and rural locations. Manufacturing plants are often located in industrial areas, rural communities, and secondary markets where carrier copper retirement timelines are accelerated and where broadband alternatives may be limited. A facility in a rural location that loses POTS service may have fewer fallback options than an urban office building.
• Production environment constraints. Unlike an office building where a technician can work during business hours with minimal disruption, a manufacturing facility has production schedules, shift patterns, and safety protocols that constrain when and how installation work can occur. Fire alarm testing and communication path verification must be coordinated with safety teams and, in some cases, with the local fire marshal or authority having jurisdiction.
• Scale of project management. A POTS replacement program across 50 or 100 manufacturing sites is a multi-year capital project. Without dedicated program management, it becomes a series of reactive one-off responses to disconnection notices, which is the most expensive and highest-risk way to execute a transition. MarketSpark’s project management capability is built specifically for this type of multi-site deployment, with structured planning from site audit through final installation.

Regulatory Requirements That Apply to Manufacturers

Manufacturing facilities operate under several regulatory frameworks that directly govern the communication systems connected to POTS lines.

NFPA 72: Fire Alarm Communication

The NFPA 72 National Fire Alarm and Signaling Code applies to every commercial building in jurisdictions that have adopted it, which includes virtually all manufacturing facilities in the United States. It governs how fire alarm panels communicate with monitoring centers and emergency services.

Fire alarm panels certified under older NFPA editions were designed around analog POTS signaling. Replacing the communication path requires a solution that replicates analog signaling behavior, not just a VoIP line. Standard VoIP does not reliably support the tonal signaling protocols fire alarm panels use to transmit alarm data.

OSHA Emergency Communication Requirements

OSHA 29 CFR 1910.165 governs employee alarm systems in manufacturing environments. It requires that alarm systems be capable of alerting all employees in the affected area and that the communication system be maintained in reliable working condition. While OSHA’s standard does not specify POTS as the required technology, it does require that communication systems work reliably. A fire alarm panel that cannot reach a monitoring center because its POTS line has been disconnected creates OSHA compliance exposure on top of the NFPA 72 issue.

State and Local Fire Codes

Beyond NFPA 72, many states and municipalities have their own fire code requirements that reference or expand on the national standard. The authority having jurisdiction in each location determines which edition of the fire code applies and what is required to maintain compliance during a communication path transition.

ASME A17.1: Elevator Communication

Manufacturing facilities with passenger elevators or freight elevators used by personnel are subject to ASME A17.1 requirements for emergency communication. Any replacement for elevator POTS lines must provide two-way communication capability and maintain operation during a building power outage.

Why Standard VoIP Is Not the Answer for Industrial POTS Lines

The instinct to replace all POTS lines with VoIP is understandable from a cost perspective but creates significant risk in a manufacturing context.

• Fire alarm signaling. As with any other industry, fire alarm panels require analog signaling that standard VoIP does not reliably provide. This is non-negotiable from a compliance standpoint.
• Industrial modems. SCADA systems and legacy PLCs that use built-in dial-up modems rely on the continuous electrical characteristics of an analog POTS line to establish connections. VoIP introduces latency, packet loss, and codec conversion that break modem handshakes. A SCADA modem that cannot connect to its host system is an operational problem. In some configurations it is a safety problem.
• Serial devices. Some manufacturing equipment uses managed serial access over POTS lines for remote monitoring and control. These connections require the same analog interface fidelity as fire alarm panels and industrial modems.

MarketSpark’s M-Series solution is purpose-built for this challenge, providing connectivity for 2-wire analog, 4-wire T1/PRI, and serial devices over 4G LTE, 5G, and Ethernet. It is the right answer for manufacturing environments where device diversity and legacy equipment constraints make a standard VoIP swap inappropriate.

What a Well-Executed Manufacturing POTS Transition Looks Like

MarketSpark’s manufacturing case study shows what is possible at scale: a leading manufacturer successfully completed POTS replacement across more than 240 locations, achieving full digital transformation of life-safety connectivity and voice infrastructure, with 24/7/365 support and flat-rate predictable billing replacing the volatile costs of legacy copper service.

The elements that make a manufacturing POTS transition successful at this scale:

• A complete line audit first. Every site, every line, every connected device documented before any replacement decisions are made. This almost always surfaces lines that nobody knew existed, particularly industrial modem connections and legacy security system lines.
• Device-specific replacement mapping. Fire alarm panels, elevator phones, industrial modems, gate dialers, and fax machines each have different replacement requirements. A single replacement technology does not fit all of them. The audit output should include a recommended replacement for each line type, validated against the applicable compliance requirements.
• Phased execution prioritizing life-safety. Lines connected to fire alarm panels and elevator phones carry the highest regulatory and safety risk. They should be transitioned first, well ahead of any anticipated disconnection notices, with compliance verification at each site upon completion.
• Production-aware installation scheduling. Installation windows must be coordinated with plant management to avoid production disruptions. This requires a provider with the nationwide installation capacity to deploy across multiple sites simultaneously on a coordinated schedule, not a sequential one-at-a-time approach.
• Centralized visibility post-transition. Once replacement is complete, facilities, operations, and compliance teams need visibility into the status of every line across every location. MarketSpark’s Command Center Platform provides real-time status monitoring, call detail records, and location-level reporting across the entire portfolio, replacing the black box of legacy copper with a managed, visible, and supportable infrastructure.
• Connectivity backup where needed. For manufacturing facilities in locations where fixed-line infrastructure is limited or unreliable, 4G/5G wireless WAN provides connectivity independent of the local carrier infrastructure, ensuring that both POTS replacement lines and broader internet connectivity remain available even if the primary wired connection fails.

Frequently Asked Questions

• POTS Replacement