Facsimile Line Voltage Detection Threshold Adjustment
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Solution Overview
Problem
Conventional facsimile apparatuses require user intervention to set and adjust line voltage settings, leading to complications and false off-hook detections when line voltage varies or external telephones are changed.
Innovation Solution
A facsimile apparatus with a storage unit for line connection standards, first and second detection units for line-open and line-capture voltages, and determination units to set a threshold voltage for off-hook detection, using line parameters and direct-current resistance, allowing automatic prevention of false off-hook detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user operation is used to measure and set line voltage, then the system can detect off-hook state, but the operation becomes complicated and requires repeated user intervention when line voltage varies or telephones are changed
Solution Approach 1:
The system automatically measures line voltage and determines off-hook detection threshold voltage without requiring user intervention. The determination unit automatically calculates the threshold based on measured voltages and stored parameters, eliminating the need for manual setup and repeated user operations when line conditions change.
Solution Approach 2:
The system pre-stores multiple line voltage parameters corresponding to different connection standards in the storage unit. When a line is connected, the system automatically selects and uses the appropriate pre-stored parameters for threshold calculation, preparing the system in advance for various line conditions without requiring user configuration.
2Extent of automation
If conventional voltage measurement method is used, then off-hook detection is possible, but false detection occurs when external telephone is changed or line voltage varies
Solution Approach 1:
The system changes the parameter used for off-hook detection from a fixed reference voltage to a dynamically determined threshold voltage. The determination unit calculates the threshold based on the relationship between line-open voltage and line-capture voltage, adapting the detection parameter to actual line conditions to prevent false detection.
Solution Approach 2:
The system uses feedback from voltage measurements to automatically adjust the off-hook detection threshold. By continuously monitoring line voltage characteristics and recalculating the threshold based on measured values, the system adapts to line voltage variations and telephone changes, maintaining accurate detection without false positives.
3Adaptability or versatility
If fixed reference voltage is used for off-hook detection, then detection is simple, but the system cannot adapt when line voltage varies or connection standards change
Solution Approach 1:
The system segments the voltage measurement process into distinct phases: measuring line-open voltage, measuring line-capture voltage, and calculating threshold based on these measurements. The storage unit stores parameters for different connection standards, allowing the system to handle various line conditions through structured, modular measurement and calculation steps.
Data Source
AI summary
A facsimile apparatus includes a storage unit, a first detection unit, and a second detection unit. The storage unit stores a parameter based on a connection standard of a telephone-line connected to the facsimile apparatus, and an apparatus direct-current resistance of the facsimile apparatus. The first detection unit detects a first voltage that is a voltage at a line-open time of a telephone line connected to the facsimile apparatus. The second detection unit detects a second voltage that is a voltage at a line-capture time of the telephone line. By using the first voltage, the second voltage, the parameter, and the apparatus direct-current resistance, a voltage to be a threshold for determination of line capture is determined. By using a voltage detected from the telephone line and the voltage to be the threshold determined by the first determination unit, whether the telephone line is captured is determined.