Daisy Chained Analog Video
Original Publication Date: 2000-Dec-01
Included in the Prior Art Database: 2003-Jun-18
The mechanism being disclosed is a daisy chained analog video solution that addresses the key requirements that yield a high quality video "front of screen". One that has a video output with crisp colors and fonts, with proper luminance contrast, as well as proper full scale luminance, while keeping the cost of implementation to a minimum. Presently, when there are several computer systems installed in a rack, the connections to the KVM (Keyboard, Video display, Mouse) console devices is usually performed by means of a KVM switch/multiplexer such as available commercially with brand names such as Apex*, Cybex* and others. This requires a cabling approach that is expensive, bulky, and cumbersome. This is due to the fact that fairly long cables must connect each system's KVM connectors to the appropriate port connectors in the switch multiplexer, three device connector pairs resulting in a total of six connectors for each "system to KVM switch" connection This is further complicated when the quantity of systems to be multiplexed is greater than the number of ports supported by a single switch multiplexer usually four or eight). In such a case, the KVM switch must be connected in a tier cascade scheme thereby requiring even larger amounts of cabling. See Figure 1. 1 An alternate solution consists of connecting the systems to the KVM devices in a daisy chain fashion starting with a cable from the "OUT" connector of a system to the KVM devices, its "IN" connector is connected to the "OUT" connector of the system downstream in the daisy chain, and so on, until the last system in the chain which does not have any system connected to its "IN" connector. This would replace the bulky, cumbersome and lengthy cabling and the switch/multiplexers (and the need for supplying power for them) with chaining cables. See Figure 2.