Demystifying POTS Line: Everything You Need to Know About it


Choosing between traditional telephony and modern solutions has become a pivotal decision for organizations of all sizes.

Plain Old Telephone Service (POTS), a legacy system that has been the backbone of voice communication for over a century, is now being challenged by Voice over Internet Protocol (VoIP) and Unified Communications as a Service (UCaaS).

These newer technologies offer a range of advanced features and benefits that are reshaping how businesses operate.

This article will delve deeper into various aspects related to POTS Line, such as:

  • The connectivity requirements and scalability of POTS and VoIP/UCaaS
  • The differences in initial setup, ongoing maintenance costs, and POTS and VoIP/UCaaS pricing models.
  • The range of features offered by POTS versus VoIP/UCaaS, including support for advanced communication needs

By understanding these distinctions, businesses can make informed decisions about their communication infrastructure to meet their needs in the digital age better.

Interesting, isn’t it?  Let’s delve deeper without further ado.

What is a POTS?

A POTS (Plain Old Telephone Service) line is an analog phone line that operates over twisted-pair copper wires provided directly by the local telephone company.

This technology dates back to the late 1800s and uses a low-energy power source to transmit sound and signal the ringer, allowing cl1assic telephones to function without batteries or charging.

During its peak in the 1990s, POTS had hundreds of millions of subscribers in the United States, and many millennials grew up with a POTS line at home.

POTS is sometimes called the Public Switched Telephone Network (PSTN). While similar, POTS refers explicitly to the phone service technology, whereas PSTN refers to the public calling network.

Although POTS lines still exist, they are increasingly being replaced by modern methods, with VoIP (Voice over Internet Protocol) phone systems being the most popular due to their cost-effectiveness.

How Do POTS Lines Work?

The Plain Old Telephone Service (POTS) setup has remained unchanged for decades. Despite numerous upgrades to phone handsets, the copper wire connection has persisted.

POTS Networking

POTS works by establishing a dedicated circuit between two telephones during a call. Historically, operators manually connected calls, but today’s system is automated and primarily digital.

Here’s how a call works over a POTS line:

Analog Signaling

  • Signal Conversion:

The handset’s microphone converts sound waves from the caller’s voice into analog electrical signals. These signals travel through the copper wire network to reach the receiver’s phone.

  • Network Interface:

Separate telephone lines within a building converge in a network interface box. This box merges the lines into a single service line from the phone company.


  • Analog Signal Transmission:

Analog signals are sent from the caller’s telephone to the receiver’s phone over copper lines.

  • Early Telephony:

Initially, wires were directly run between telephones, making long-distance calls expensive.

  • Cost Reduction via Switches:

Centralized switches were introduced to reduce costs and were positioned at network points known as telephone exchanges. These exchanges connect multiple POTS lines, determining the most efficient call path.

  • Communication Nodes:

Switches serve as communication nodes, routing calls through local, regional, national, or international switches.

Dedicated Call Circuits

  • Call Initiation:

When a caller dials a phone number, the receiver’s phone rings. Answering the call establishes a direct, exclusive connection (dedicated circuit) between the phones.

This circuit switching ensures a reliable connection, allowing both parties to converse without interference from other calls.

The dedicated circuit is reserved for one call at a time.

Signal Decoding and Voice Reconstruction

  • Signal Decoding:

Analog signals are decoded at the receiver’s end to reconstruct the original sound waves.

  • Voice Playback:

The caller’s voice is heard through the telephone speakers as audible sounds, completing the communication loop.

  • Call Termination:

The call ends when one party hangs up, disconnects the dedicated circuit, and returns the line to standby mode, ready for another call.

What Is a POTS Line Used for?

POTS (Plain Old Telephone Service) lines are still used today for their consistent, secure, and straightforward communication capabilities. Here are a few everyday use cases:

1. Fax Transmission and Reception

POTS lines are used to transmit scanned documents between fax machines, a technology that was widely prevalent a couple of decades ago.

2. Credit Card Processing Systems

POTS lines are reliable for processing credit card transactions, especially in areas with limited internet access.

Traditional credit card processing services often rely on POTS lines for their connectivity.

3. Security and Alarm Systems

Due to their reliability, older security and alarm systems use POTS lines. These systems maintain a dedicated line to monitoring centers or emergency services and typically work even during power outages.

4. Elevator Communication Systems

POTS lines are ideal for elevator communication systems with limited internet access. They provide a direct and reliable line to emergency responders, ensuring solid emergency connectivity.

5. Digital Subscriber Lines (DSL)

DSL (Digital Subscriber Line) uses POTS lines to deliver high-speed internet. This requires additional investment from telephone companies to provide high-bandwidth connectivity, special modems, and noise filters to separate traditional voice and data signals.

While POTS lines remain valuable for these purposes, modern alternatives are available, such as:

  • Online Faxing: Online faxing has become a more efficient alternative to analog faxing.
  • Cellular Alarm Systems: It provides a modern security and alarm systems solution, leveraging cellular service for connectivity.

Recommended Read: Digital Makeover of the UK’s Telephone Network – Great British to be Switched Off by December 2025

What are the Pros and Cons of POTS?

POTS (Plain Old Telephone Service) technology has proven its resilience. While it has notable advantages, significant disadvantages also need to be considered.

Here’s a detailed analysis of the pros and cons of POTS lines:

Advantages of POTS Lines

1. No Dependency on Power or the Internet

POTS lines function without needing an external power source, as they are powered through the telephone. This ensures that the phone service remains operational during power outages.

Unlike modern communication methods, POTS lines do not require an internet connection, making them reliable in areas with poor or no internet service.

2. Compatibility with Legacy Equipment and Infrastructure

POTS lines work seamlessly with existing copper wire infrastructure, eliminating the need for expensive upgrades or replacements.

They are compatible with older telephone systems and devices, such as fax machines and analog modems, which many businesses and homes still use.

3. Ease of Use

Most people are familiar with traditional telephones, making POTS lines extremely user-friendly. Their straightforward nature means users have little to no learning curve.

4. Stability and Dependability

POTS lines provide a stable and secure communication channel, especially in emergencies.

They are known for their dependable performance, with fewer service interruptions than internet-based communication methods.

Disadvantages of POTS Lines

1. Limited Features

Traditional POTS lines typically lack advanced features such as caller ID, call forwarding, call waiting, voicemail, and video conferencing, which are standard in modern communication systems.

POTS lines’ limited feature set makes them less appealing to businesses requiring more phone system functionality.

2. Higher Costs

Maintaining the copper wire infrastructure and telephone systems can be costly and labor-intensive.

Additional phone jacks and lines can be expensive, especially in more significant buildings or multiple locations.

3. Maintenance-Heavy Systems

POTS’s copper lines require regular maintenance and are susceptible to damage from inclement weather and physical disruptions.

Repairing damaged lines can take hours or even days, leading to extended service interruptions.

4. Lower Voice Quality

POTS lines often have lower voice quality than digital alternatives and are more prone to noise and interference. Weather conditions and physical damage to the lines can significantly degrade call quality.

5. Inflexible Technology

POTS is considered outdated technology, and many countries, like the UK, are phasing it out in favor of more advanced solutions, such as fiber optics.

POTS’s analog nature makes it difficult to scale or adapt to modern communication needs.

POTS vs. VoIP: A Comparison

Here’s a detailed comparison between POTS (Plain Old Telephone Service) and VoIP (Voice over Internet Protocol):

Feature POTS VoIP
Technology Analog uses copper wires for connection Digital uses the internet for connection
Call Quality Stable, but lower quality, susceptible to noise and interference High quality, dependent on internet speed and stability
Power Dependency Independent of external power, works during power outages Dependent on internet connection and power
Internet Dependency It does not require an internet connection Requires an active internet connection
Mobility Fixed to a specific location Highly flexible, it can be used on mobile phones, desk phones, and computers.
Features Limited (caller ID, call forwarding, call waiting, voicemail) Rich feature set (video calls, multimedia sharing, instant messaging)
Cost Higher costs, including maintenance and installation Lower costs, significant savings on calls, especially long-distance
Scalability Difficult to scale Easily scalable, can add or remove lines with ease
Maintenance Requires regular maintenance of physical lines Minimal maintenance, primarily software-based
Security High, physical lines are hard to intercept Varies, can be secured with encryption and proper network security
Reliability Highly reliable, less prone to outages Dependent on Internet reliability
Business Adoption Decreasing, being phased out This is increasing, especially with the rise of remote work
Use Cases Fax machines, credit card processing, security systems, elevator phones Business communications, remote work, personal communication apps

POTS vs. UCaaS

As businesses increasingly transition from traditional telephony to modern communication solutions, understanding the differences between POTS (Plain Old Telephone Service) and VoIP/UCaaS (Unified Communications as a Service) is crucial.

Below is a detailed comparison in terms of benefits and costs.

Feature POTS UCaaS
Technology Analog, copper wire-based Digital, internet-based
Connectivity Requires copper wires and dedicated telephone lines Requires stable internet connection
Scalability Limited, requires physical installation and maintenance Highly scalable, easy to add/remove users via online portals
Pricing High setup and maintenance costs, additional fees for features Subscription-based, lower overall costs, often include updates
Features Basic (caller ID, voicemail, call waiting) Advanced (video calls, multimedia sharing, instant messaging, IVR)
Mobility Fixed location, tethered to physical lines High mobility, can be used on multiple devices anywhere
Maintenance High, requires regular physical upkeep Low, primarily software-based, with regular updates
Reliability High, independent of power and internet outages Dependent on internet and power, but offers redundancy options
Security High, physical lines are hard to intercept Variable can be secured with encryption and proper network security
User Management Complex requires telecom company intervention Easy, managed through online admin portals
Integration Limited Integrates with other business applications and services

POTS Vs. VoIP/UCaaS: A Comparative Analysis


POTS requires copper wires and dedicated telephone lines, which results in higher setup complexity and cost. It is also limited to fixed locations. VoIP/UCaaS requires only a stable internet connection.

It enables global connectivity without physical infrastructure, making it ideal for remote or distributed teams. While susceptible to power outages, this is a common issue across most phone systems.


Adding or removing lines is cumbersome with POTS and requires physical installation and technical assistance.

Conversely, an online portal can easily add or remove new users and numbers. There is no need for physical installations, making it flexible for growing or shrinking teams.


  • POTS: High initial setup and installation costs and ongoing maintenance expenses. Additional features like call recording or extra lines incur extra fees.
  • VoIP/UCaaS: It often includes advanced features without additional costs. There is no need for physical maintenance, and updates are handled automatically by the service provider.

Feature Set

  • POTS: It is limited to basic features such as caller ID, call waiting, and voicemail. It does not support modern communication needs like video conferencing.
  • VoIP/UCaaS: Rich feature set including video calls, multimedia sharing, instant messaging, integrated analytics, IVR (Interactive Voice Response), and automatic call distribution. Regular updates often add new features.


POTS are tethered to a physical location and specific devices. They are not flexible enough for mobile or remote work.

On the other hand, VoIP/UCaaS can be used on multiple devices (mobile phones, desk phones, computers) anywhere with an internet connection. Facilitates remote work and mobility.


POTS requires regular physical maintenance of copper lines and hardware, which can be costly and time-consuming.

Conversely, VoIP/UCaaS maintenance is mainly software-based and handled by the service provider. Regular updates ensure the system remains current without user intervention.

Wrap Up

All in all, VoIP and UCaaS represent the next evolution in telephony, offering significant advantages over traditional POTS lines regarding connectivity, scalability, pricing, features, and maintenance.

As businesses adapt to modern communication needs, the transition to VoIP/UCaaS becomes increasingly attractive, making it the future of telecommunications.

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