The choice of NTSC or PAL depends on the analog camera used. If the analog camera is the NTSC type, the IVS-2120 will output the video as the NTSC format, and vice versa.
Connect the powered analog camera to the IVS-2120 first and then power on the IVS-2120 for determining NTSC or PAL format. After that, connect the video out cable to the monitor, so that the IVS-2120 will output the correct video format to TV monitor properly.