Project related to telephone

[ajaykumar988]

I need to design an easy calling card system through which a user can input his password and call.i also need to maintain a database system through which i can keep track of the balance of the user .
The whole system must be a computer based system with either a parallel or serial port interface .

I desperately need help in this .Please help me through web sites,softwares ,circuit ideas or whatsoever means .

thanks in advance

 

[desperado1]

you read the book serial port complete by jan axleson first

 

[Ramesh_maharjan]

you should first choose the programming language and database management technique.

 

[siongboon]

You can refer to the following for serial communication circuit DIY examples,
https://www.beyondlogic.org/
**broken link removed**

To interact with the user at the other end of the telephone line,
you can use this MT8870 DTMF IC to decode the dial tone.
**broken link removed**
You can also design a ring detector using a couple of diode and transistors,
Available in the website too.
You can design detector for progress call tone to add-on more functions.


Most importantly, you need a microcontroller to control
all your devices and interface between user and computer.
I strongly recommend PIC from microchip (example PIC16F877a).
**broken link removed**
It is easy to learn and there are alot of technical support in the internet.

Enjoy your project,
Siong Boon