Ethernet Power Path Control for Fire Alarm Override
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Solution Overview
Problem
Existing IP access control systems require copper wire cabling between the Fire Alarm Control Panel (FACP) and the IP access controller for fire alarm override, which is inconvenient and may limit flexibility in installation and maintenance.
Innovation Solution
The system employs an AC-to-DC power supply and power path control logic to provide two separate power paths over Ethernet cables, allowing the fire alarm override signal to disconnect the second power path, eliminating the need for copper wire cabling and enabling fire alarm override functionality within the IP access control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper wire cabling is used between FACP and IP access controller for fire alarm override, then reliable fire alarm override signal transmission is achieved, but installation flexibility and ease of maintenance are reduced
Solution Approach 1:
The patent combines the fire alarm override signal transmission with the existing PoE power and data communication infrastructure. The FACP communicates fire alarm signals to the IP access controller through the same Ethernet network used for PoE power delivery, eliminating the need for separate copper wire cabling. This merging of functions maintains reliable signal transmission while significantly improving installation flexibility.
Solution Approach 2:
The Ethernet cable system is made multi-functional by using it for multiple purposes: PoE power delivery, IP data communication, and fire alarm override signal transmission. This universal use of a single infrastructure eliminates the need for dedicated copper wires for fire alarm signals, thereby improving installation flexibility while maintaining reliable signal transmission through the network protocol.
2Reliability
If separate copper wire cabling is installed for fire alarm override, then dedicated fire alarm signal path is provided, but device complexity and installation complexity increase
Solution Approach 1:
The patent merges the fire alarm override signal path with the existing PoE Ethernet infrastructure. Instead of installing separate copper wire cabling, the system uses the existing Ethernet cables that already carry power and data, thereby reducing cabling complexity while maintaining a dedicated functional path for fire alarm signals through protocol-level separation.
Solution Approach 2:
The patent extracts the fire alarm override signal transmission function from the physical cabling layer and moves it to the protocol/application layer of the Ethernet communication. This allows the signal to be transmitted over the existing PoE infrastructure without requiring separate physical wires, thereby reducing device and installation complexity while maintaining reliable dedicated signal paths through software/firmware control.
3Ease of operation
If PoE is used for power delivery, then dedicated power supply at door is eliminated, but fire alarm override implementation becomes more complex
Solution Approach 1:
The patent makes the PoE Ethernet infrastructure multi-functional by using it for power delivery, data communication, and fire alarm override signaling. The IP access controller, already equipped with Ethernet interface for PoE operation, receives fire alarm signals through the same network connection, eliminating the need for separate power supplies at doors while keeping fire alarm implementation simple through protocol-level handling.
Solution Approach 2:
The IP access controller, which already has the Ethernet interface and processing capability for PoE operation, is made to handle fire alarm override signals itself through its existing network stack. This self-service approach eliminates the need for additional hardware or complex external wiring while maintaining ease of power supply installation through PoE.
Data Source
AI summary
An apparatus includes an AC-to-DC power supply, with a positive terminal operatively coupled to two two-wire pairs of an Ethernet port to provide a first and second power path over a structured cable. A negative terminal is operatively coupled to a third two-wire pair of the Ethernet port to complete the first power path. Power path control logic has an input port operative to receive a two-wire input signal from an external device, and is operatively coupled to the negative terminal of the AC-to-DC power supply output, and to a fourth two-wire pair of the Ethernet port to complete the second power path. The power path control logic is operative to disconnect the negative terminal of the AC-to-DC power supply from the fourth two-wire pair of the Ethernet port in response to a two-wire input signal received at the input port, to disconnect the second power path.