i have a question.. help me to answer

i have a question about my project which is using a protcol and i am using RS232 to communicate with my PC with is using COM1 and my teacher ask me to use MAX232CPE IC chips also but why? how does the MAX232CPE work? anyone can explain to me? i also have a 8051 chips and i have done my code with TX and RX to talk to my PC.. pls reply if you know.. thank.

Hello!

First thing (that many other users should consider). Could you change your title
for a relevant one for your later posts? "I have a question, help me to answer"
does not give any hint about what you want. And on top of that, everybody knows
what a technical forum is (ie, some people ask questions and some other reply).

That said, MAX232 is a driver, and you could understand what it does by
reading its data sheet. RS232 can work in non homogeneous systems, and
the electrical levels can be a lot higher than your hardware. So this chip
adapts your hardware to the externally connected systems. Not more.

http://focus.ti.com/lit/ds/symlink/max232.pdf

Dora.

hello.. anyway thank for your reply.. max232cpe isit a level shifter? which can shifter until a voltage to talk to the COM1 which is RS232?

Good work Dora!
& for JASON :
Plz refer datasheet of max232 IC. Study the T1,2 & R1,2(in & out) & use any one combination to establish connectivity bet'n ur kit & PC.

but how about DMX512?

Hello!

You were talking about physical interfaces (MAX232 and its variants, for
example MAX3232 for 3V devices, are physical adaptor chips). Now
I don't know too much about DMX512 because I have never used it, but
it's a protocol (correct if I'm wrong!).
Before buying a MAX232 and building your hardware, it wouldn't hurt
reading a bit more about RS232 and DMX512.

Dora.

max232CPE is a level shifter and why we need this? if i can understand the datasheet i wont be asking you now. anyway thank for your reply