This is an old camera so we must use the tab for Custom URL.
Login to the camera and go to Setup and Audio and Video. There you have this
There are settings for streaming 1 and streaming 2. Use the settings for Streaming 1.
The URL, RTSP path, to connect to the camera is rtsp://cameraIP/
When adding the camera to Netcam Studio use the tab for Custom URL. Set stream type to rtsp_tcp.
In Address write:
rtsp://username:password@cameraIP/
In the camera configuration it is possible to change Resolution, Quality, Frame rate. This video format should give video and audio. Make sure that audio is enabled. When any of these parameters are changed it might be necessary to reconnect to the camera in Netcam Studio.