Digital Intercom Retrofitting Over Existing DC-Powered Cables

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Solution Overview

Problem

Existing analog intercom systems lack the ability to easily retrofit digital equipment for full-featured, multi-channel digital communications over existing cabling, limiting flexibility and functionality.

Innovation Solution

A digital intercom system utilizing a cable network with three conductive paths, including a ground path, where a master station provides DC power and bidirectional digital communications through transceivers and routers, allowing for point-to-point, point-to-multi-point, and party line communications among user stations, and enabling easy retrofitting of analog networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If digital intercom systems use CAT-5 cable with structured wiring, then digital communication capability is improved, but ease of retrofitting existing analog networks deteriorates

Engineering Contradiction:
Improvedigital communication capabilityVSAvoidease of retrofitting
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent makes the existing three-conductor microphone cable serve multiple functions simultaneously: it carries DC power from the master station to user stations, transmits bidirectional digital communications via transceivers, and provides ground reference. This multi-functionality allows digital intercom capability to be added to existing analog networks without requiring new cabling infrastructure, thus resolving the contradiction between digital capability and ease of retrofitting

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If additional cabling is installed for digital communication, then communication functionality is improved, but device complexity deteriorates

Engineering Contradiction:
Improvecommunication functionalityVSAvoidcabling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges power transmission and digital communication functions into a single three-conductor cable system. The DC power supply, transceivers for bidirectional digital communication, and ground path all share the same cable infrastructure that was originally designed for analog audio. This consolidation eliminates the need for separate power cables and communication cables, reducing overall system complexity while maintaining full digital functionality

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If existing analog cabling is used for digital communication, then ease of retrofitting is improved, but communication capability deteriorates

Engineering Contradiction:
Improveease of retrofittingVSAvoidcommunication capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the electrical parameters and communication protocol on the existing analog cable infrastructure. By applying digital signaling schemes and protocols over the three-conductor cable that was designed for analog audio, the system achieves full digital communication capability including individual addressability of user stations, multi-channel communications, and data routing without requiring physical changes to the cabling

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables flexible, multi-channel digital communications with individual addressability of user stations, simplifies setup and reconfiguration, and maintains robustness and reliability similar to analog systems while providing fault tolerance and easy installation.

Implementation Method 1

A master station includes: (a) a DC power supply connected to the first, second and third conductive paths, where the DC power supply powers the at least one user station

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2420004B1Digital intercom network over DC-powered microphone cable
Publication Date: 2019.06.05 CLEAR COM LLC
  • EP2420004B1 patent drawingFigure 1a
  • EP2420004B1 patent drawingFigure 1b
  • EP2420004B1 patent drawingFigure 2a~2d

AI summary

A digital intercom system provides DC power and multi-channel bidirectional digital communications over existing cabling such as microphone cabling used in analog intercom networks. Three or more conductors in the cabling are used for both transmitting and receiving digital signals and carrying DC power. The digital intercom system includes digital user stations and a digital master station which can be used to retrofit an existing analog intercom network or deployed in a new network. User stations can be connected to the cabling via drop cables which do not use active electronic components. The master station routes digital audio and control data packets in three or more channels based on respective network addresses of the user stations to provide point-to-point, point-to-multi-point, and party line communications among the user stations. Sessions and groups can be configured which define talker and listener user stations.