DTMF Encoding for Elevator Data Transmission
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Solution Overview
Problem
Existing communication methods between elevator installations and remote servers face challenges, particularly with the disappearance of switched telephone networks, requiring a more reliable and easier-to-implement solution for data transmission.
Innovation Solution
A method involving encoding digital data from sensors and control data using a combination of frequencies between 200 Hz and 3600 Hz, transmitted as an analog signal, allowing for transmission over conventional twisted lines or optical fibers, and utilizing DTMF encoding for robust and reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FSK modulation is used to transmit digital data from sensors to a remote server, then data transmission can be established over telephone lines, but the system becomes complex and data loss occurs due to the high-speed modulation requirements
Solution Approach 1:
The patent replaces complex electronic FSK modulation systems with a simpler analog audio signal transmission system. Instead of using high-speed digital modulation, the invention uses human voice frequency range analog signals (300-3400 Hz) that can be transmitted over existing telephone infrastructure without requiring complex modems or high-speed communication protocols. This substitution dramatically reduces system complexity while maintaining reliable data transmission.
Solution Approach 2:
The invention changes the transmission parameter from high-speed digital FSK modulation to low-frequency analog audio signals in the 300-3400 Hz range. By encoding data as audible tone frequencies rather than high-speed digital transitions, the system achieves reliable transmission over standard telephone lines without requiring complex high-speed modulation equipment, thus reducing both device complexity and data loss.
2Adaptability or versatility
If IP converters and optical fibres are equipped in each lift installation to enable communication without switched telephone networks, then communication can be maintained, but the implementation becomes more complex and costly
Solution Approach 1:
The patent creates a universal communication method that works across multiple network infrastructures (traditional telephone lines, optical fibers, and mobile networks) using the same simple analog audio signal approach. By designing a system that encodes data as audible tones in the 300-3400 Hz range, the solution can be deployed on any existing communication infrastructure without requiring specialized IP converters or optical fiber installations, thereby maintaining implementation ease while achieving network adaptability.
Solution Approach 2:
The invention introduces an intermediary encoding layer that translates digital sensor data into analog audio signals within the 300-3400 Hz voice frequency range. This intermediary representation allows the data to be transmitted through any voice-capable channel (telephone lines, optical fibers with voice channels, mobile networks) without requiring infrastructure-specific hardware, thus simplifying implementation while maintaining versatility across different network types.
3Productivity
If high-speed FSK modulation is used for data transmission, then data can be transmitted quickly, but data loss increases and communication reliability decreases
Solution Approach 1:
The patent uses periodic audio tone signals in the 300-3400 Hz range to transmit data, where each data element is represented by a specific frequency or combination of frequencies. This periodic analog signaling is inherently more robust against noise and interference than high-speed digital modulation, as the human voice frequency range is well-established for reliable communication over telephone infrastructure. The periodic nature of the tones allows for easier detection and reduced data loss while maintaining adequate transmission speed for elevator monitoring applications.
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
This method provides a simple, reliable, and cost-effective means of transmitting measurement and control data, enabling efficient preventive maintenance and remote control of elevator installations, even in the absence of traditional fixed telephony networks.
Implementation Method 1
encoding said digital data by associating with each data element a combination of at least two frequencies chosen from a predetermined set of frequencies in the frequency band between 200 Hz and 3600 Hz
Implementation Method 2
transmitting an analog signal obtained by, for each data element, simultaneously generating at least two sinusoids each corresponding to one of said at least two frequencies
Data Source
AI summary
The invention relates to a method of communication between a lift installation (1) and a remote server (17), the method comprising - receiving digital measurement data (Sensor_data(n)) from the at least one sensor and/or digital control data (Ctrl_data(n)) from the remote server and intended for a management device controlling the lift installation, - performing a DTMF encoding to encode said digital measurement or control data, and - transmitting, to the remote server or the management device, an analogue signal (DDTMF(t); EDTMF(t)) corresponding to this DTMF data encoding, this analogue signal being in the conventional fixed telephony frequency band.