Multi-screen display controllers are used to control and project multiple images on the same screen. Input signals, output signals, other specifications and features are important parameters to specify when searching for multi-screen display controllers. Other specifications to consider may include power, mounting, and image controls. With multi-screen display controllers, common choices for power are 115 VAC, 230 VAC, and DC.  Mounting options include desktop or stand-alone, panel or chassis mount, rack mount, and DIN rail.  Image controls include scaling, positioning, overlay, genlock, zoom, saturation, contrast, brightness, and freeze.  Common features for products with multi-display inputs include time or date stamping, front control panel, multilingual programming, and remote control support.

Multi-screen display controllers carry input signal specifications such as the number of inputs, standards, formats, horizontal scan rate, and vertical scan rate. The number of inputs specifies the maximum number of simultaneous video signal inputs from cameras, recorders, etc.  Video input standards choices include NTSC< 3.58/4.43 NTSC, PAL, SECAM, RS170, RS330, HDTV, and CCIR.  Input formats for multi-input display processors include RGB, Y PbPr, Y/C (S-Video), composite, DVI, and SDI.  Horizontal scan rate is the length of time an electron gun takes to move across one line (horizontal) of the screen. It is measured as the frequency at which horizontal sync pulses start the horizontal retrace for each line. A high frequency is needed for a non-interlaced scan. The horizontal sync frequency for NTSC is 15.75 KHz.  Vertical scan rate is the length of time an electron gun takes to repeat one entire screen (vertical). With multi-screen display controllers, vertical scan is measured as the frequency of the vertical sync pulses or vertical scans. NTSC vertical scan frequency is 59.9 Hz.

Output signal specifications to consider when selecting multi-screen display controllers include number of outputs, standards, formats, resolutions, and multiple display options.  The number of output channels specifies the maximum number of video signal outputs to devices such as monitors and recorders.  Video output standards for multi-screen display controllers include NTSC< 3.58/4.43 NTSC, PAL, SECAM, RS170, RS330, HDTV, and CCIR.  Output formats include RGB, Y PbPr , Y/C (S-Video), composite, DVI, and SDI.  Choices for output resolutions include 640 x 480 (VGA), 800 x 600 (SVGA), 1024 x 768 (XGA), 1280 x 1024 (SXGA), and 1600 x 1200 (UXGA).  Multiple display options include picture-in-picture (PIP), quad, nine, and sixteen.