Demarc Extension Diagrams

A demarc extension is defined as:

The transmission path originating from the interface of the access provider’s side of a telecommunications circuit Demarcation Point within a premise and ending at the termination point prior to the interface of the edge Customer Premises Equipment. This may include in-segment equipment, media converters and patch cords as required to complete the circuit’s transmission path to the edge CPE.

The following diagrams show the various configurations that may occur when extending a circuit’s demarcation point. These diagrams and terminology will accelerate fault isolation and communications between parties when a demarc extension is suspect for circuit issues.

It is recommended to test from the interface side of the access provider’s demarcation point to isolate the telecom circuit from the demarc extension. For details about specific items, please refer to our Terminology section.

Single Segment Demarc Extension Diagrams

Click the picture to enlarge. For terminology, click here.
Single Segment
Direct Connect / Direct Connect
Single Segment
Indirect Connect / Indirect Connect
Single Segment
Direct Connect / Indirect Connect
Single Segment w/ Media Converter
Indirect Connect / Indirect Connect
Single Segment
Indirect Connect / Direct Connect

Multi-Segment Demarc Extension Diagrams

Multi-Segment
Direct Connect / Direct Connect
Multi-Segment
Indirect Connect / Indirect Connect

Additional Demarc Extension Diagrams

MPOP Extension

In some instances, the circuit is delivered outside of the facility and will require a MPOP Extension in addition to the demarc extension.

Demarc Pre-Wire

The Demarc Pre-Wire is not interfaced into the local access providers’s side of the Demarcation Point and thus is not a demarc extension.

Patch Cord Testing
A demarc extension by definition is a complete channel, which can include patch cords or cross connects. However due to installer responsibilities, patch cords may be the requirement of another party and must be noted upon testing of the demarc extension by:

  1. Tested with patch cord
  2. Tested without patch cord

This will provide accelerated fault isolation if the circuit is not working properly upon another party supplying patch cords at circuit turn up.

Additional Information
Specified connections for a demarc extension will fall into one of four types and will vary on a case-by-case basis:

  • Direct/Direct
    The demarc extension is directly connected to both the Demarcation Point and the eCPE without the use of additional connections such as patch cords.
  • Indirect/Indirect
    The demarc extension requires additional connections such as patch cords to interface with the Demarcation Point and the eCPE.
  • Direct/Indirect
    The demarc extension is directly connected to the Demarcation Point, however requires additional connections such as a patch cord to interface with the eCPE.
  • Indirect/Direct
    The demarc extension requires additional connections such as a patch cord to interface with the Demarcation Point, however it is directly connected to the eCPE.

More Information

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