Variable Impedance Adapter for Telephone State Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High speed DSL systems face challenges in providing reliable power supply to network modems at distribution points, and existing VOIP solutions struggle to detect telephone on-hook/off-hook states accurately due to reverse power feed interference, especially when only a single copper pair is used.
Innovation Solution
A telephone on-hook/off-hook state communication system with a variable impedance adapter unit that detects changes in impedance at a predetermined frequency, allowing accurate detection of telephone state transitions even with reverse power feed, using a micro-filter-like device that includes a sensor to detect changes in resistance or current through the copper pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse power feed is used to supply power to network modem at distribution point, then power supply reliability is improved, but detection of telephone on-hook/off-hook states becomes inaccurate due to interference
Solution Approach 1:
The patent introduces frequency domain differentiation by applying AC signals at specific frequencies (e.g., 16kHz for off-hook detection, 20kHz for on-hook detection) to distinguish telephone states. This dimensional change from DC-only reverse power feed to multi-frequency AC signaling enables accurate detection despite the presence of reverse power feed interference.
Solution Approach 2:
The patent uses AC coupling capacitors and bandpass filters as intermediary elements to separate the detection signals from the DC reverse power feed. These intermediaries allow AC detection signals to pass while blocking DC interference, enabling accurate telephone state detection in the presence of reverse power feed.
2Device complexity
If single copper pair is used for both DSL and telephony, then device complexity is reduced, but ability to detect telephone states accurately deteriorates due to reverse power feed interference
Solution Approach 1:
The patent makes the single copper pair universally functional by implementing frequency-division multiplexing. The same two-wire connection carries both DSL data signals and telephony signals with AC coupling, eliminating the need for separate wiring while maintaining detection accuracy through frequency-based signal separation.
Solution Approach 2:
The patent changes the electrical parameters of the copper pair by superimposing AC detection signals at specific frequencies on top of the DC reverse power feed. This parameter change enables the system to encode telephone state information in the frequency domain rather than relying on separate wiring configurations.
3Power
If conventional VOIP solution is used with reverse power feed, then power supply capability is improved, but detection of telephone on-hook state becomes unreliable
Solution Approach 1:
The patent employs periodic AC signaling at distinct frequencies to detect telephone states. By periodically applying 16kHz signals during off-hook detection and 20kHz signals during on-hook detection, the system creates reliable periodic patterns that can be distinguished from the continuous DC reverse power feed, ensuring dependable state detection.
Solution Approach 2:
The patent replaces the mechanical/electrical direct connection detection method with electromagnetic field-based AC signal detection. Instead of relying on direct electrical continuity that is obscured by reverse power feed, the system uses AC coupling and frequency-specific detection to sense telephone states through electromagnetic signal interactions.
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 reliable detection of telephone on-hook/off-hook states without interference from reverse power feed, allowing seamless integration with existing DSL and VOIP systems, even in scenarios with only a single copper pair, and supports two-wire solutions for telephony and data services.
Implementation Method 1
a variable impedance and means for changing the impedance of the variable impedance such that a property of the impedance at a predetermined frequency greater than zero changes in response to the telephone apparatus transitioning between an on-hook state and an off-hook state
Implementation Method 2
the second part including a detector for detecting the change in the impedance of the variable impedance of the first part via the pair of conductors
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A telephone on-hook/off-hook state communication system (1 ) comprises a first part (40), for example in the form of an In-Line Analogue POTS presentation Adapter, which is operable to interconnect between a telephone apparatus (50) and a pair of conductors (242,245), and a second part (300) operable to interconnect between the pair of conductors (242,245) and a telephone adapter unit (32), the first part including a variable impedance (42) and means (43) for changing the impedance of the variable impedance (42) such that a property of the impedance at a predetermined frequency (f) greater than zero changes in response to the telephone apparatus (50) transitioning between an on-hook state and an off-hook state, the second part (300) including a detector for detecting the change in the impedance of the variable impedance (42) of the first part (40) via the pair of conductors (242,245).