# US 5,889,775 A · Multi-stage switch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,889,775 A - Document ID: US5889775A - Status: Granted - Kind: A - Application number: 08/908,288 - Filed: 1997-08-07 - Granted: 1999-03-30 - Earliest claimed: 1995-08-07 - Assignees: BE Aerospace, Inc. - Inventors: Conrad Jan Sawicz; Victor Cecil Kemp; Arvind Chimanlal Desai - Web page: https://patentgrep.com/patent/US5889775A ## CPC - H04Q 3/68: Grouping or interlacing selector groups or stages - H04Q 2213/13003: Constructional details of switching devices - H04Q 2213/1302: Relay switches - H04Q 2213/13034: A/D conversion, code compression/expansion - H04Q 2213/1304: Coordinate switches, crossbar, 4/2 with relays, coupling field - H04Q 2213/1308: Power supply - H04Q 2213/13093: Personal computer, PC - H04Q 2213/13141: Hunting for free outlet, circuit or channel - H04Q 2213/13166: Fault prevention - H04Q 2213/1319: Amplifier, attenuation circuit, echo suppressor - H04Q 2213/13291: Frequency division multiplexing, FDM - H04Q 2213/1332: Logic circuits - H04Q 2213/13337: Picturephone, videotelephony - H04Q 2213/1337: Operator, emergency services - H04Q 2213/13393: Time slot switching, T-stage, time slot interchanging, TSI - H05K 1/14: Structural association of two or more printed circuits (providing electric connection to or between printed circuits H05K1/11, H01R12/00) - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract The present invention provides a multi-stage switch. An input or first stage receives a plurality of information signals. An output or third stage distributes a plurality of information signals. A middle or second stage establishes a plurality of signal paths between the input stage and output stage. The switch includes a routing function which selects the path between the input stage and the output stage. The routing function includes a reallocation function which reallocates existing paths to free paths to avoid signal blocking. ## Claims ### Claim 1 A switching unit comprising: input means for receiving a plurality of information signals wherein the input means includes circuit boards having multiple layers to receive analog and digital information signals and multiple input switches; output means for distributing a plurality of the information signals wherein the output means includes multiple output switches; crosspoint means for establishing a plurality of paths between the input means and the output means wherein the crosspoint means includes multiple crosspoint switches; and routing means for selecting a path between the input means and the output means through the crosspoint means, the routing means including means for reallocating existing paths by examining paths previously selected by the routing means and a new paths for the reallocation of paths from the input means, through the crosspoint means and to the output means to thereby overcome blocking of the new path between the input means and the output means and optimize the paths through the crosspoint means wherein the reallocation means partitions the existing paths and the new path into at least a first and second matching wherein first matching contains connections between the input switches and the output switches not common to connections between the input switches and the output switches in the second matching and deallocates the existing paths and reallocates the connections of the first matching to paths through one crosspoint switch and the connection of the second matching to paths through another crosspoint switch. ### Claim 2 (depends on 1) The switching unit of claim 1 wherein the input means, the crosspoint means and the output means are each printed circuit boards and wherein the crosspoint board is orthogonal to the input board and the output board is orthogonal to the crosspoint board. ### Claim 3 (depends on 2) The switching unit of claim 2 further comprising a video back plane printed circuit board having connections for the input board to mount orthogonal to the crosspoint board and for the output board to mount orthogonal to the crosspoint board. ### Claim 4 (depends on 2) The switching unit of claim 2 wherein the printed circuit boards are multilayered. ### Claim 5 (depends on 2) The switching unit of claim 2 wherein the printed circuit boards include integrated circuits to switch information signals between the input means and the output means. ### Claim 6 (depends on 1) The switching unit of claim 1 wherein the input means comprises at least one crosspoint switch. ### Claim 7 (depends on 1) The switching unit of claim 1 wherein the output means comprises at least one crosspoint switch. ### Claim 8 (depends on 1) The switching unit of claim 1 wherein the crosspoint means comprises at least one crosspoint switch. ### Claim 9 (depends on 1) The switching unit of claim 1 wherein the routing means comprises: computing means for establishing the paths; and memory means for storing a map of the established paths. ### Claim 10 (depends on 1) The switching unit of claim 1 wherein the reallocation means examines each path previously established by the routing means at most once to establish a new path. ### Claim 11 (depends on 1) The switching unit of claim 1 wherein the reallocation means examines each output means at most once to establish a new path. ### Claim 12 (depends on 1) The switching unit of claim 1 wherein the reallocation means includes a packing means for finding the optimum paths through the crosspoint means. ### Claim 13 (depends on 1) The switching unit of claim 1 further comprising a second input means for receiving a plurality of information signals. ### Claim 14 (depends on 13) The switching unit of claim 13 wherein the input means receives non-broadcast information signals and the second input means receives broadcast information signals. ### Claim 15 (depends on 13) The switching unit of claim 13 wherein the input means, the crosspoint means, the second input means and the output means are each printed circuit boards and wherein the crosspoint board is orthogonal to the input board and the output board is orthogonal to the crosspoint board. ### Claim 16 A switching unit comprising: input means for receiving a plurality of information signals wherein the input means includes circuit boards having layers to receive analog and digital signals and a differential receiver circuit to convert information signals into single ended signals for distribution through the switching unit, output means for distributing a plurality of the information signals; crosspoint means for establishing a plurality of paths between the input means and the output means, and routing means for selecting a path between the input means and the output means through the crosspoint mean, the routing means including means for reallocating existing paths by examining paths previously selected by the routing means and a new path for reallocation of paths from the input means, through the crosspoint means and to the output means to thereby overcome blocking of the new path.