Telephone Line Voltage Stability Detection for Hook State
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication systems falsely detect changes in line direct-current voltage as on-hook/off-hook states of external telephones due to causes other than the telephone's state, leading to incorrect hook detection.
Innovation Solution
A communication apparatus with a first determination unit for assessing voltage stability and a second unit for determining if the voltage is below a threshold, ensuring accurate detection by distinguishing between stable and unstable voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage detection system is used to detect on-hook/off-hook states, then hook detection can be performed, but false detection occurs when voltage variation is caused by factors other than telephone state changes
Solution Approach 1:
The detection process is divided into multiple independent determination stages: a first determination unit assesses voltage stability by comparing voltage values over time, while a second determination unit checks if voltage falls below a threshold. Only when both conditions are satisfied is an off-hook state declared, preventing false detection from single-factor voltage variations
Solution Approach 2:
The system continuously monitors line direct-current voltage and uses feedback from the first determination unit (voltage stability assessment) to control the operation of the second determination unit (threshold comparison). This feedback mechanism ensures that threshold comparison is only performed when voltage stability confirms a genuine state change, eliminating false detections
2Device complexity
If simple voltage threshold comparison is used, then detection is simple, but false detection occurs due to voltage variations from causes other than telephone state
Solution Approach 1:
The detection system is segmented into two functional units: the first determination unit that assesses voltage stability by comparing voltage values across different time points, and the second determination unit that performs threshold comparison. This segmentation adds minimal complexity while dramatically improving detection accuracy by eliminating false positives from transient voltage fluctuations
Solution Approach 2:
Before performing the critical threshold comparison to detect off-hook state, the system first performs a preliminary stability assessment by the first determination unit. This preliminary action filters out unstable voltage conditions that would cause false detection, ensuring that only genuine telephone state changes trigger the detection alert
Data Source
AI summary
An apparatus to which a telephone line can be connected, the apparatus comprising: a first determination unit configured to determine, based on a change amount of a line direct-current voltage from the telephone line per time period, whether the line direct-current voltage is stable; a second determination unit configured to determine whether the line direct-current voltage from the telephone line is a first threshold or lower; and a third determination unit configured to, if the first determination unit determines that the line direct-current voltage is stable and if the second determination unit determines that the line direct-current voltage is the first threshold or lower, determine that the external telephone has captured the telephone line.