Vlb - Video Loop Back - Extron electronics System 8 User Manual

. VIDEO LOOP BACK (VLB)
· NORM.AL MODE
VLB.MODE
VLB RESTRICTIONS
Video Loop Back (VLB) is a special "double switching" function performed by the System 8/10 that makes
the switcher compatible with either composite-to-RGB decoders and scan doublers. When VLB is active
and standard RGB inputs are selected, RGB video signals exit the switcher through the normal RGB
output connector set. When composite video or S-Video signals are selected, they exit the switcher
through their normal composite video or S-Video output connector sets and are routed to the external
decoder or scan doubler. The RGBS output of the decoder or scan doubler is then "looped back" to the
l�st input (input 8 or 10) of the switcher. RGBS output to the projector exit the switcher through the
normal RGB output connector set. This allows the System 8/10 to switch only RGB signals to the display
device
The VLB mode is turned on and off by a toggle switch located between input connector sets 7 and 8 on
the rear panel of the System 8/10, see diagram. With the switch in the NORM (up) position, the VLB
mode is disabled. In the VLB (down) position, video loop back is enabled .
VLB Switch Set to NORM: When composite and S-Video input signals are selected they are routed
directly to the projector (or display monitor) through the normal composite and S-Video output connec-
tor set .
VLB Switch Set to VLB: When a composite or S-Video input signal is selected, it is first output through
the normal composite or S-Video output connectors to an external (user provided) composite-to-RGB
decoder or scan doubler. The RGBS output of the decoder or scan doubler is "looped back" to the last
input of the System 8/10. The decoded (or scan doubled) RGBS signal is then routed directly to the
projector (or display monitor) through the System 8/10 RGBS output connector set .
When using the VLB mode with looped switchers, always connect the switchers in a Star Configuration .
The VLB mode cannot be used when switchers are connected in a Daisy-Chain configuration. Only the
Primary switcher can use the VLB mode---peripheral switchers cannot. Refer to Chapter 5 for instructions
on looping switchers in the Star Configuration .
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VLB - VIDEO LOOP BACK

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System 8/10 User's Manual
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Page 3-13