Article Details

Abstract

To address the lack of missed call alerts in most existing landline phones, which can lead to missed important calls, a sound and light alarm system for landline missed calls based on an AVR microcontroller (ATmega16) is designed and implemented. The system processes the telephone line signal through a preconditioning circuit for voltage reduction and level shifting. The ADC module of single-chip microcomputer samples and analyzes the features of the processed signal, accurately identifying telephone states-idle, ringing, off-hook, and on-hook-using a Finite State Machine (FSM) model. When a ring is detected without a subsequent off-hook action within a set time, the system activates audible and visual alarms via an optocoupler-isolated driver circuit. Test results demonstrate that the system accurately identifies states across various calling scenarios and triggers alarms reliably, effectively alerting users to missed calls and thereby reducing potential risks associated with unanswered calls.

Keywords

landline phone; missed call; Single-chip Microcomputer; alarm system

References

1. [1] Chen Jianjun, Xie Feng, Wang Xiaowu, etc Design of Digital Torque Wrench Control System Based on PIC Microcontroller [J]. Sensors and Microsystems, 2022, 41 (3): 72-75
2. [2] Wang Peng, Pan Dong Research on Liquid Level Automation Control System for Paper Manufacturing Based on Single Chip Microcomputer [J]. Paper Science and Technology, 2024, 43 (8): 51-54
3. [3] Zu Yikang, Xu Miaojing Design of Temperature Intelligent Control System Based on Single Chip Microcomputer and PID Algorithm [J]. Modern Electronic Technology, 2024, 47 (8): 83-89
4. [4] Guo Zhi, Zhang Ying, Lin Song, etc A leakage prevention alarm system for unmanned substations based on microcontrollers [J]. Shandong Electric Power Technology, 2019, 46 (11): 51-55
5. [5] Chong Zhewen, Cheng Haoxin Design and Implementation of Intelligent Voice Lighting Control System Based on Single Chip Microcomputer [J]. Internet of Things Technology, 2023, 13 (7): 148-151
6. [6] Chen Jiaorong, Chen Yan, Chai Baofa, etc Research on the Design of Emergency Communication System for Nuclear Power Plants [J]. Nuclear Science and Engineering, 2024, 44 (6): 1395-1402
7. [7] Liang Yunjie, Han Lin Thoughts and Countermeasures on Emergency Communication Support for Subway under Extreme Conditions [J]. Fire Science and Technology, 2022, 41 (12): 1720-1723
8. [8] Ren Wei, Zhu Jun Research on the Planning of Shanghai Urban Rail Transit Official Telephone System [J]. Urban Rail Transit Research, 2021, 24 (11): 56-59
9. [9] Que Lihua Optimization and Transformation of Shanghai Rail Transit Dedicated Dispatch Telephone Network Based on Softswitch [J]. Urban Rail Transit Research, 2020, 23 (S2): 75-78
10. [10] Lin Lifeng, Zhou Zijian, Jiao Bingli Implementation of Physical Layer Secure and Confidential Telephone [J]. ZTE Technology, 2025, 31 (2): 77-82

About the authors

Hu Jiayao (2005-), male, Han ethnicity, from Wuhan, Hubei Province, is currently pursuing a bachelor's degree with a research focus on embedded systems and IoT applications.