RS232: Detect cable disconnect when no flow-control

[josborne]

Hi everyone.  Thanks for all your thoughts and ideas.  

The device is a Philips patient monitor such as this, and we can't change the device hardware.  I do utilize a heartbeat signal, but its only every ~12 seconds.  I could make it more frequent, but bandwidth is an issue ... its a complex device and a complex interface, and the device itself can only send a limited amount of data.

As many have suggested, including BertMcMahon, a fast heartbeat appears to be my best solution.  I'll try that. 

Thanks everyone!

[BertMcMahan]

Don't forget that the heartbeat doesn't have to be a full data download. It just needs to be something to see if it's connected. For example, many devices "Get ID" command that returns a version number or something. It shouldn't affect your datarates.