Electronic Private Automatic Branch Exchange System with Four Extensions Implementation

Title of the project: Electronic Private Automatic Branch Exchange System with Four Extensions Implementation for Office Intercommunication
Domain: Embedded Systems Design
Software: Embedded C, Keil, Proload
Microcontroller: AT89S52
Power Supply: +5V, 500mA Regulated Power Supply
Transmitter Display: LED 5mm, 16 X 2 LCD
Receiver Display: LED 5mm, 16 X 2 LCD
Input Source: Key Pad
Crystal: 11.0592MHz
Communication Device: Standard DTMF Telephone Instrument
Applications: Home / Office inter communication

ABSTRACT

EPABX plays a vital role in office inter communication. An EPABX is basically a telephone switch that is used by businesses that is at their business location. EPABX is an abbreviation that stands for Electronic Private Automatic Branch Exchange. Companies typically use multiple-line systems to handle their incoming and outgoing phone calls, letting their phone carrier handle the management of those lines. In this scenario, four lines come into the business and are all visible on a multiple-line phone.
The private branch exchange (EPABX) provides internal station-to-station communications for a well-defined set of users. It also provides access to outside telephone lines, called trunks, which connect the private branch exchange to the telephone company's central office.
With this project one can talk to another person of other department from his desk without moving from his place. The reception can transfer the outside call to any of the extension, if needed. This project is designed for two trunk lines and four extensions.
This project uses regulated 5V, 500mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/12V step down transformer.



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