Browse Prior Art Database

Intra Primary Switch Connections in a Blocking System

IP.com Disclosure Number: IPCOM000094819D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Johnson, LL: AUTHOR

Abstract

The primary switch matrix is for a four-wire crosspoint telephone switching system. N lines in the primary switch connect to secondary switches, not shown, via 2N-1 links. The secondary switch provides connections to other primary switch matrices in the remainder of this system. For simplicity, each line labeled S for send or R for receive actually represents two wires, giving a total of four wires for each telephone line, i. e., two represented by S and two represented by R. Note the lower left portion of the drawing.

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Intra Primary Switch Connections in a Blocking System

The primary switch matrix is for a four-wire crosspoint telephone switching system. N lines in the primary switch connect to secondary switches, not shown, via 2N-1 links. The secondary switch provides connections to other primary switch matrices in the remainder of this system. For simplicity, each line labeled S for send or R for receive actually represents two wires, giving a total of four wires for each telephone line, i. e., two represented by S and two represented by
R. Note the lower left portion of the drawing.

To set up a telephone conversation between any two subscribers, the S wires of one subscriber must be connected to the R wires of the other and vice versa. Interprimary switch connections are set up in the usual manner. lntraprimary switch connections are established and the proper send-receive relationships are maintained between two subscribers by utilizing N extra crosspoints. These are switches 10-11, 12-13, 14-15, and 16-17 corresponding to links 7, 6, 5, and 4 in the drawing, where N = 4. When selecting links to make normal interprimary connections, the links are scanned from link 1 to link 7. The nonspecial links 1, 2 and 3 are therefore allocated to line use before the links with the extra crosspoints are chosen. The link scanner is reset after every connection, assuring that an available link is selected from the nonspecial links.

For example, intraprimary switch connections between a s...