AVTRON CAMERAS GIVES B&W DISPLAY?

It is generally video signal types selection issue. Check the first DVR types if DVR is HD-TVI/CVI/AHD and supposed to your camera not converted as according to DVR types. Example: if your DVR is HD-TVI and your camera is in AHD or CVI Mode it will give B&W display on monitor screen or some time it even no display on DVR.