Using RS232 modem lines like CTS / RTS to detect physical connection

[josborne]

Hi,

I am building a simple VI for communicating with an RS232 instrument.  The instrument is old and there is little documentation.  But I got it working.  Now I am simply trying to add a quick function to the beginning of the VI to detect if the device is physically connected to my serial port (without actually opening the port and initiating communication).

I believe this might be possible by using NI-VISA to check the state of the model serial lines (like DTR / DSR / CTS / RTS).  I think I remember hearing that if the RS232 receiver sets one of these lines HIGH, then the sender responds in some way.  Any thoughts here?  

- John

[nicolas.pj]

Hi josborne,

Perhaps you may be interested in the VISA Find Resource Function
http://zone.ni.com/reference/en-XX/help/371361R-01/lvinstio/visa_find_resource/

Cheers