Communication Apparatus Hook-Up Detection Using Voltage and Signal Merging
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Solution Overview
Problem
Communication apparatuses connected to phone lines face issues in accurately detecting the hook-up state of external telephones due to voltage reductions caused by factors other than telephone usage, leading to erroneous notifications and processes.
Innovation Solution
A communication apparatus equipped with a line-voltage detecting unit and a communication-signal detecting unit, which determines the hook-up state based on a reduction in line voltage and the presence of communication signals, preventing false positives from other voltage reductions, such as power saving modes or connection defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If line voltage detection is used to determine external telephone hook-up state, then detection cost and device size are reduced, but detection accuracy deteriorates due to false positives from other voltage reductions
Solution Approach 1:
The patent combines line voltage detection with communication signal detection to determine hook-up state. Both detection results are integrated in the control device, which determines hook-up state only when both conditions are met: line voltage is at first threshold or lower AND communication signal is detected. This merging approach maintains the low cost and small size of using SDAA while eliminating false positives from other voltage reductions.
Solution Approach 2:
The system uses feedback from multiple detection sources (voltage level and communication signal presence) to verify hook-up state. The control device continuously monitors both parameters and adjusts its determination based on the combination of readings, ensuring accurate detection while maintaining simple hardware architecture.
2Measurement precision
If current detection is used to determine external telephone hook-up state, then detection accuracy is improved, but device complexity and cost increase due to required current detecting circuit and optical coupler
Solution Approach 1:
The patent replaces the mechanical/electrical current detection system with an electrical field-based voltage detection system using the SDAA's line-voltage detecting function. This substitution eliminates the need for current detecting circuits and optical couplers, reducing device complexity and cost while maintaining adequate detection accuracy through the addition of communication signal detection.
3Measurement precision
If line voltage threshold is set low to avoid false positives, then detection accuracy improves, but legitimate hook-up detection may be missed when voltage reduction is minimal
Solution Approach 1:
The control device merges voltage threshold detection with communication signal detection to resolve the threshold setting dilemma. By requiring both conditions to be true (voltage at threshold AND communication signal present), the system can use a more lenient voltage threshold without increasing false positives, thereby maintaining reliable detection of legitimate hook-up events.
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
Accurate detection of external telephone hook-up states, reducing errors and enhancing user experience by differentiating between legitimate hook-up signals and other voltage reductions, and enabling efficient power management in facsimile transceivers.
Implementation Method 1
The SDAA has a function of detecting a voltage of a phone line (hereinafter, referred to as a line voltage)... the line voltage means an inter-cable voltage between two conductive cables constituting the phone line
Implementation Method 2
when the external telephone is hooked up such that the phone line is closed, as described above, a DC loop is formed and a current flow
Data Source
AI summary
A communication apparatus, which is connected to a phone line, and to which an external telephone is connectable to. The communication apparatus includes: a line-voltage detecting unit which detects a line voltage; a communication-signal detecting unit which performs detection on a communication signal, which is input to the communication apparatus from the phone line or from the external telephone upon the external telephone is hooked up; and a control device which performs a hook-up determining process of determining that the external telephone is in a hook-up state when the line voltage detected by the line-voltage detecting unit is equal to or less than a first threshold value and the communication signal is detected by the communication-signal detecting unit.