Title: RS232 Interface Module

METHODOLOGY (10)


CONTENT:

Schematic Diagram of RS232 Interface Module

The MAX232 is an integrated circuit (IC), first created by Maxim Integrated Products, that converts signals from an RS232 serial port to signals suitable for use in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals.

The receivers reduce RS-232 inputs (which may be as high as ± 25 V), to standard 5 V TTL levels. These receivers have a typical threshold of 1.3 V, and a typical hysteresis of 0.5 V.
The later MAX232A is backwards compatible with the original MAX232 but may operate at higher baud rates and can use smaller external capacitors – 0.1 μF in place of the 1.0 μF capacitors used with the original device.

RS-232 is a telecommunications standard for connecting certain types of electronic equipment. In computer networking, RS-232 cables were commonly used to connect modems to the compatible serial ports of personal computers. So-called null modem cables could also be connected directly between the RS-232 ports of two computers to create a simple network interface suitable for transferring files. 

In my project, RS232 as a connector to convert analog to digital signals which from PIC to GSM module (SMS). MAX232 is an IC that convert the signals. It's came along with RS232 serial port and combined together in one circuit. 5 capacitors are used together to stored energy because the RS232 is connected directly from power supply. Capacitors are stores an electric charge and releases it when required.

OBJECTIVE:

1.) To learn how to interface or construct the RS232 connector between PIC and GSM module.

2.) To understand the function of each components and applied it on the board.

CONCLUSION:

This part is quiet interesting because it involve the way how to convert the signals (analog-digital) by using MAX232. Furthermore, I don't have any experience about that and finally its done and function very well, even though facing some problems and need to troubleshoot again and again.