... 4. RS-232 control visual presenter technical specificationNew High Pixels Visual Presenter22X optical zoom ,8X digital zoomModel 2800HV2800SD2800SVOptical partslensF1.6 ... Image freeze,Mirror,Colorful/ Black and White,Divide Screen,Text / Image Mode,Positive/ Negative,Brightness adjustment ... Image freeze,Mirror,Colorful/ Black and White,Divide Screen(image split)Text / Image Mode, Lighting partsAssistant ...