I'm not sure the best place to put this, but I've been working on integrating our ptz cameras into our Crestron AV system. Specifically bringing the cameras in and out of standby remotely since they are in hard to reach places. I was testing the VISCA over IP commands and have realized that the CAM_Power off command is not actually putting the cameras into standby.
At first I thought I was sending the command incorrectly as the cameras didn't seem to react. Normally the green light on the cameras illuminate and the cameras stops responding to controls when the IR remote is used to put the cameras into standby, but then I realized when the power off command was sent the video output went black so it was indeed receiving the command however the light does not illuminate and the camera is still completely controllable, it just mutes the video output.
Am I doing something incorrectly or is this the expected outcome using VISCA over IP?
I just tested this out myself and I was able to confirm some of what you described. The Standby light does not come on when the CAM_Power_Off command is sent using VISCA over IP.
However, the video feed did cut out as expected and I was no longer able to issue any PTZ control commands either over IP or with the IR remote. So it appears the camera is in Standby mode, the only issue being that the Standby light does not turn on.
One thing I did notice after putting the camera into Standby, with the VISCA over IP command, is that if I attempted to control the camera with the IR remote the Standby light would come on at that point.
I will pass this info along to the Engineering team.
In the meantime, I would make sure that the cameras you are working with have the latest firmware. You can download the latest firmware from the Firmware Finder.
And here is the link to the most up to date VISCA over IP command set.
I did speak with engineering about this and there are known issues with how the Cam_Power On & Off commands function. So the behavior you and I saw is not unexpected at this time.
Hopefully this is something that can be addressed with future firmware updates to the cameras.