RS232 Communication - Can I use it to create a steady state signal?

Question

In all honesty, I think the answer is "no;" however, I want to get a second opinion. Basically, I need one micro-controller device to send a steady signal to another one, but the communicate between them is using RS232. So I think that I have to create/update the communication messages to get it to do what I want.

What do you think?

Answer 1

You should be able to set something like DTR (Data Terminal Ready), pin 20, or DSR (Data Set Ready), pin 6, high and keep it there as your steady-state signal. This is how modems/terminals detect that there is a device on the other end that is ready to communicate. It all depends on what level of access you have to the hardware through your driver.

[EDIT] This doesn't involve sending data, although you could still do that using TX/RX, pins 2 & 3.

RS-232 Reference on wikipedia

Answer 2

You mean a fixed voltage? Not a square wave? (the letter U) What about a break command (if you want to call it a command)?

Certainly you can use one of the control lines if that helps...Or are you specifically looking for something out of the TX?