RS232 Control LED without MCU

Hi,

Is it possible without MCU directly using RS232 to control some output device?

At this moment i just only need to control one LED and one Buzzer.
I just need to control 2 output signal. So, hope can design a very simple and no costly design and i just only have serial port TXD and RXD pin only.
I had seen other people did before, they had using MAX232 as a driver to control 2 output but i'm not sure whether their thing is work fine not.

Thank you.

well Help...

Is it possible without MCU directly using RS232 to control some output device?

by that i understand u mean directly from pc serial port.... if yes then read on ...

leds and buzzers are simple on off devices... and need no protocols..
by using TXD and RXD as GPIOs u can do the switching....
check the voltage level at ur pc port.. i beleive.. it is enough to drive a led.. for buzzer if u want to make the sound a little more audible u will need a current booster kinda thing...
altogether yes.. u can control these devices from serial port....

how to control TXD and RXD as GPIOs?...
Because whatever data sent to serial port, follows a standard RS232 format...
usually with one start bit + 8 data bits + one stop bit(usually). imagine if you wanted to control an LED tied to TXD pin, then u need to send 0xFF to serial port continuously. and using human perception rate, we can even comprise on data rate (and data value also)

But if you want to control one more buzzer independent of LED then i think you require controller to do this job. I may be wrong also.. please clear the matter....

why don't you make use of parallel port? its better than using UART as GPIO

since u need to control just 2 outputs so u have an option of using DTR and RTS signals.
except TX,DTR,RTS all the other signals are read only for ur pc.u can make a simple application that toggles DTR,RTS on/off

A very intelligent answer abbas