International Business Machines Corporation

Richard Dambricourt

Jean L Calvignac

Bernard Brezzo

Christian Garcia

Mohamed Badaoui

Yves Granger

Sylvie Spalmacin-Roma

Andre Masclet

Jean-Pierre Sanche

Jean-Paul Franquenouille

A scanning protocol is provided for the scanning of a plurality of serial transmission lines connecting users' devices to the scanning means of a communication device, said lines being coupled to the scanning means through line interface couplers (LICs) having each a wired address (n,n', . . . ) known to the scanning means. This scanning protocol requires that for each LIC configuration, a given LICn having a wired address n be re-addressable with a logical address n' corresponding to the wired address of any other active LICn'. This is done in order to determine, for said LIC configuration, the shortest possible scanning scheme including all the active LICs. The re-addressing of a LICn of wired address n, with a logical address n', includes the steps of: resetting the LICn to be affected a logical address n'; setting the logical address n' into LICn; locking said logical address n' into said LICn, and enabling the lines (26) connected to LICn re-addressed with logical address n'.

Protocol and apparatus for selectively scanning a plurality of lines

A line scanning device which operates under the control of a microprocessor connected to a control memory in which a memory location area is assigned to each line is provided for a line adapter in a communication controller for receiving or sending message bits in series from or to terminals connected to the lines using any protocols. It comprises a first store which includes a first and a second memories, an area being assigned to each line in each of the memories which can be read and written in the same time and a second store which includes a single memory in which a storage location area is assigned to each line. These stores are addressed by a control and address unit which includes first and second address counters under the control of an elementary time counter, the first counter outputting the address information relating to the first store during time t provided for scanning a line, and the second counter outputting the address information relative to the second store during time nt, n being at least equal to 4, and control circuitry receiving said address information and the elementary time information for providing at the outputs of the control and address unit, memory address and read/write control information at times selected during the scanning period and sequentially, the addresses of the present lines which are scanned.

Communication line scanning device for a communication controller

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Cagnes Sur Mer, France

Richard Dambricourt