Need help on creating interface circuit for RS232

Dear Friends
I hope someone can help me on this problem. I am working on a project in my workplace to create a interface circuit for RS232. My problem is, I need to detect a LED and a relay turned on. Once these 2 device has been turned on, I need to detect the signals from both and send it thru RS232 to trigger my software. I am attaching the part of the circuit which shows the LED and Relay. Hope someone can show how to tap the voltage or current from these device and feedback to RS232 by creating a interface circuit which software able to detect it.


Thanks

Dear Friends
I hope someone can provide some help over here. I am thinking off to connect a AND gate. Since AND gate has 2 end. 1 end connects to relay and another end connects to LED. Can this works? If both LED and relay turn on, the AND gate turned on and the output will be logic 1. Then I can use this to detect thru the RS232 port. Hope someone can guide me from here. I am not good at circuit design but I know to write program to verify the logic 1. thanks

You have mixed things a bit and the picture is not clear, and this could be a reason for not getting responces so far.
What exactly are you trying to do? What does a relay or a LED have to do with serial communication? What is the exact problem? Reading from those components or send data through RS232? They are two different tasks. How can a relay and a LED build an interface circuit for RS232? What this interface circuit is supposed to do? Is there an MCU involved or just the PC?

Alexandros

Dear ECCMOT,
I think you mixed different different types of data as alexxx said..First of all, rs232 connection needs a info exchanging protocol which is between two microprocessors. One is your pc and other can be a microcontroller or any gsm module.. I think in your project you must need a microcontroller.. You have to program it to detect signals from led and relay and then implement rs232 protocol in it also with program... according to the sensing the microcontroller will then send data through rs232 to trigger the software..
Do you work with MCUs?? You have to learn both programming and implementation of hardware. For now you can use transistors to amplify signals from led and send it to MCU by configuring one of it's port as input... Finally you have to make a clear statement about what you actually want to do?

Best of luck..

Rocket Scientist

Dear Alexxx / Rocket Scientist
Thanks for pointing out that my posting is not clear. OK Let me try to explain it in the manner that is easy to comprehend. My problem is I have a external circuit which contains a relay and a LED. Once the external circuit is activated, it will turn on the LED and Relay for a short while and turn off. I would like to trigger my software in the PC to prompt me if it detect the LED and relay has been turned on thru the RS232 serial port connected to this external circuit. I hope this explanation is clear. Let me know if this is not.
I know that we need a MAX232 IC to convert the RS232 protocol to TTL logic. The input of the MAX IC is connected to RS232 port and then the output of the MAX232 need to connect to the LED and Relay circuit. I hope someone can point me out how to connect the output of the MAX232 IC to the LED and Relay circuit shown on my first post. thanks

Dear ECCMOT,
Your problem is a bit clear now... But to implement the rs232 protocol with external circuit you will need a microcontroller which will communicate with your pc through rs232..As far as I know, you can't take usable signals from led and relay directly to use on rs232... But you can do it over a function of microcontroller called USART. You can plug led to microcontroller to know it's state and then send this info tp pc byrs232 which can trigger your software.. Hope this helped..But still I cant understand how will your ext. circuit be activated?? Where is the controller??
Best of luck...
Rocket Scientist

Dear Rocket Scientist
Thanks for your reply. I read thru a web link which mentioned that we can interpret the external circuit by detecting the CTS signal going hi and low. We can create a switch which will turn on once the LED or Relay turned on. Once the circuit turn on, there will be 12V flow to CTS which we able to detect. Thanks for your reply.

Oh that's nice. But I don't know about this CTS detection method. Would you please post that helpful link here??

Dear Rocket Scientist
Sure. Please go to this link to get info. **broken link removed**. thanks