What to do with monitors that have TTL level inputs ?
This type of monitors do not have much use with modern PC graphics cards. TTL level monitors have very limited number of colors and limited gray scale. TTL level interface uses different signal levels in picture signals than PC VGA card (TTL signal is 0V or 5V and analogue VGA RGB uses 0.7Vvv signal levels). The sync signals in TTL monitors have the same levels than PC VGA card which also uses TTL level sync signals. TTL level monitors typically only have two available intnsisties in each color component: on and off. Typically the monitors have also an extran intesity bit, which will (when activated) turn all color components which are on to the intensified state (more output level). The interface which has RGB and intensity bits is usually called to have RGBI interface. RGBI interface supports 16 colors. RGBI monitors are used many older computer systems (for example PC CGA card). Some TTL level monitors (IBM EGA monitor etc.) have two bit input and support typically three levels: bla
