Motion detector connect to RS232

Hi. Im new on this forum and i dunno english so well so sorry for few language mistakes!
I have a work to do. I need to connect motion detector to a computer. I want to do this by RS232. From detector are two signal outputs, so i connect it to pins number 4 and 7 (RTS and DTR). It is right?? How to test this connection??

In next step on my work, i have to write program (in C++). For begining, when detector detect a motion on the screen will appear a message like "Attention, motion detect".

Can somebody help me??:>

We have no idea what motion detector you're using, typically they only offer high/low outputs, you can't feed that into an RS232 serial port and expect results. You could in theory use a signalling like (like RTS CTS DTR etc..) as an on/off detector but you'd still need to level adjust the signal and poll the serial port.