Pelco Developer Network (PDN)

Discover whether working camera connected to NET5404T encoder

I am using a C# program to grab a still from each of our video cameras periodically, for upload to our web site.

If a camera is not working, I upload a standard image file.

When a camera is not working, the encoder returns an image whose size varies, so I can't use the image size to tell that the camera's not working or not connected.

Is there a way to query the encoder to ask if its camera is working? The encoder obviously can detect when a camera's not working, because it puts up a still image under that circumstance, but I can't find any documentation of how to make the encoder report on camera status.

For one encoder whose camera is not working, I've found, on subsequent runs of my program, that I've received stills of the following sizes :

16062 bytes, 16070 bytes, 16094 bytes.

Is there, perhaps, a way of configuring the encoders so that they always send exactly the same size file, instead?