Multiplex communications – Wide area network – Packet switching
Patent
1981-08-04
1985-06-04
Brown, Thomas W.
Multiplex communications
Wide area network
Packet switching
179 18AD, 179 18ES, 370 68, H04M 356, H04Q 354, H04Q 1104
Patent
active
045218790
ABSTRACT:
A digital private automatic branch exchange provides a plurality of ports which may comprise line trunks or operator circuits, the ports being grouped with each group being controlled by an individual microprocessor circuit which performs all real time control over the ports. Voice communication between ports is effected by time division multiplex in connection with a digital switch system forming part of a common control which is controlled by a central processing unit responsive to the microprocessors in each port group for assigning time slots to each interconnection channel. Isolation between the central processing unit and the rest of the system is provided by a peripheral bus to which the common control units and port groups are connected, which peripheral bus is connected to the CPU bus by way of an interface circuit, permitting the system to operate with various types of central processing units without redesign of the peripheral units. A conference circuit is also provided for making available a range of conference sizes by combining the available lines to the conference circuit into groups of a predetermined size which may be expanded by combining groups to form conferences of larger or intermediate size.
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"New Digital PABX Family", by R. C. Garavalia, GTE Automatic Electric Journal, May 1977, pp. 303-311.
"The GTD-1000 Digital PABX", by R. C. Wegner, GTE Automatic Electric Journal, Mar. 1977, pp. 262-268.
Breidenstein Charles J.
Gueldenpfennig Klaus
Narula Karam V.
Oswald William A.
Russell Stanley L.
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