Demarcation Point (Demarc): A Complete Guide

Demarcation point origins date back over 100 years to when phone companies wanted to isolate network issues to improve service quality.

Today, demarcs continue to serve the vital purpose of clarifying who is responsible for any problems with voice, data, video, and other services.

They also enable companies to provide enhanced offerings by extending their networks right up to the customer’s building.

In this article, we will have a deep knowledge of demarcation point (demarc), its uses, and types in detail.

What is a Demarcation Point or Demarc?

A demarcation point (demarc) in telecommunications defines the boundary between the facilities provided by the telephone company or other communications service provider and those provided by the customer.

It establishes a clear delineation of ownership and maintenance responsibilities.

The demarcation point is the physical location that separates the provider’s network from the customer’s premises wiring.

  • Demarcs were first established by AT&T in an 1878 order that required telephone companies to provide and maintain lines up to the customer’s premises. This defined where the provider’s responsibility ended and the customer’s began.
  • The demarcation point is sometimes referred to as the network interface device (NID), minimum point of entry (MPOE), or smart jack. It can consist of a plastic box on an exterior wall, a terminal block inside a building, or another access point.
  • Having a defined demarcation simplifies troubleshooting by eliminating confusion over whether network problems exist on the customer or provider side of the demarc. It helps resolve disputes quickly.
  • Demarcation establishes ownership of equipment. The provider is responsible for their equipment up to the demarc, while the customer owns and maintains equipment on their side.
  • Larger buildings often have a main demarcation point with multiple customer demarcs branching off. This allows providers to extend their network to the property.

A Brief History of the Demarcation Point

The demarcation point has its origins in the early days of telephony in the late 1800s.

Here is a brief overview of the history and evolution of the demarc point:

  • 1878 – The Pacific Telephone Telegraph Company installed the first telephone demarcation points between their network and customer premises equipment. This establishes clear maintenance boundaries.
  • 1934 – The Federal Communications Commission was created to regulate telephony. They formalize demarcation requirements for all telephone companies.
  • 1984 – The Bell System is broken up. Demarcation points become important in distinguishing networks of new local exchange carriers.
  • 1996 – The Telecommunications Act requires incumbent local exchange carriers to provide competitive local exchange carriers access to customers through demarcation points.
  • Early 2000s – As VoIP and other new technologies emerge, demarcation remains important for delineating ownership and maintenance.
  • Today – Demarcation continues separating provider and customer equipment with outdoor network interface devices, terminal blocks, and other access points. It remains a core concept for communications services.

Uses of a Demarcation Point

Demarcation points serve several important functions in communications networks and services:

  • Establishes clear boundaries for ownership, responsibility, and maintenance between provider and customer equipment.
  • Simplifies troubleshooting by eliminating ambiguity over whether network issues originate on the customer or provider side of the demarc.
  • Resolves disputes over responsibility for repair costs when network problems arise.
  • Allows providers to extend their network infrastructure right up to the customer premises.
  • Enables providers to offer enhanced services through the deployment of customer premises equipment.
  • Allows multiple service providers to deliver services to the customer premises without interfering with each other’s network.
  • Facilitates interconnection between provider and customer for local area networking.
  • Provides a physical point of access to the provider’s network for testing and monitoring performance.
  • Allows customers to easily disconnect or change services by accessing provider connections at the demarcation point.
  • With a clear handoff point, the provider can validate performance and verify the customer is getting the services being billed for.

Different Types of Demarcs

There are a few common types of demarcation points deployed in telecom networks:

  • Outdoor Network Interface Device (NID) – This weatherproof box mounted on the outside of the customer premises contains connections and termination equipment. It often uses a 66-type punch-down block.
  • Indoor Wall-Mounted Terminal Block – Instead of a box outside, this simple terminal block mounts on an interior wall to establish the demarc point.
  • Building Entrance Terminal (BET) – The demarcation point for a large multi-tenant building is often a BET housing connection and termination equipment for providers.
  • Fiber Optic Enclosures – For fiber internet and communications links to customer buildings, outdoor fiber optic demarcation enclosures house and protect fiber terminations.
  • Equipment Rack or Cabinet – A server room or wiring closet may have a dedicated rack or cabinet establishing the demarcation point for data center and office LAN links.
  • Minimum Point of Entry – This term refers to the closest point to the building entrance where a provider can establish the demarcation without actually going outside.
  • Network Interface Device (Smart Jack) – This self-contained device can plug directly into phone jacks to establish the demarcation point anywhere inside.
  • Main Distribution Frame (MDF) – The MDF or main phone closet in vintage buildings contains punch-down blocks establishing old-school demarcation points.

Global Demarcation

While demarcation originated in the U.S. telephone system, it is now a global practice for communications providers and customers worldwide:

  • Americas –Demarcation remains very common in North America and Latin America for both traditional POTS and newer IP-based voice and data services.
  • Europe – The EU standardizes rules for demarcation including right up to the optical network termination device. Demarcation is a well-established practice.
  • Asia – Countries like China, Japan, and India follow demarcation standards very similar to the U.S. with outdoor boxes and indoor terminal blocks.
  • Africa – Demarcation is formalized in standards and carrier operations across Africa. Some countries utilize mobile demarcs.
  • Australia – The Australian Communications and Media Authority provides guidance on demarcation for the NBN national broadband access network.
  • Middle East – Demarcation is a standardized practice across this region in countries like Saudi Arabia, UAE, Qatar, Israel, and others.
  • Global carriers – Multinational providers utilize demarc globally for their enterprise data services and underwater cable landing stations.

Looking for the Right Business Phone System?

As a business shopping for a new phone system, understanding demarcation is an important part of assessing providers and offerings:

  • Seek platforms that enable easy management of call routing at the cloud level without needing access to on-site PBX equipment. This gives you full control right up to the demarc.
  • Make sure the provider offers service level agreements guaranteeing uptime and reliability for any equipment they install on your side of the demarc.
  • Ask about options for redundant internet connectivity from multiple providers to avoid having a single point of failure at the demarc.
  • Inquire about support for direct routing between branches over the provider’s VoIP network without touching your LAN. This improves performance by skipping your internal demarc.
  • For maximum flexibility, look for a system that allows BYOD hardware policies and uses the cloud for call control, routing intelligence, and VoIP packet transmission.
  • A hosted VoIP architecture where all call routing happens in the cloud allows seamless scalability as your business grows without on-premise hardware concerns.

Understanding upfront where the line of responsibility lies between provider and customer equipment will help ensure the smoothest implementation and highest reliability going forward.

Frequently Asked Questions (FAQ)

Ques 1: What does the acronym DMARC stand for in telecom?

Ans: DMARC stands for Demarcation Point, the physical boundary between the facilities provided by a communications service provider and those provided by their customer.

It establishes who is responsible for equipment on each side.

Ques 2: Where are demarcation points typically located?

Ans: Most commonly, demarcs are located in a weatherproof box on the exterior of a building for outdoor access.

They can also be found in interior wiring closets on a wall-mounted terminal block or equipment rack.

Ques 3: Who owns and maintains the equipment on each side of the demarcation point?

Ans: The service provider owns and maintains all facilities on their side of the demarc up to and including the demarcation device itself.

The customer owns and is responsible for all wiring, equipment, and cabling on their side beyond the demarc.

Ques 4: How does demarcation impact service level agreements and uptime guarantees?

Ans: SLAs only apply to provider-owned equipment up to the demarc. Anything beyond that point is the customer’s responsibility.

Demarcation delineates what falls under the provider’s SLA.

Ques 5: Can customers access, alter, or disconnect communications facilities at the demarcation point?

Ans: Yes, the demarc provides the handoff point between provider and customer equipment.

Customers can alter wiring and disconnect or change services on their side as needed through the demarc.

Evelyn Brown
Evelyn Brown

Evelyn Brown is a knowledgeable and dedicated reviewer of business communication softwares. When she's not testing the latest platforms or providing in-depth analyses for his readers, you can find her playing guitar and hiking local trails.