Abstract: A remote access system for a trader turret telephone switching network. A line status display is created at the remote site using the Internet as a data channel. A line command can be entered remotely using a “mouse” (or other graphical interface) and communicated back to the switching network via the Internet. A voice channel can then be established to the remote site via the public telephone switching network or via the Internet.

Abstract: A clocking mechanism with improved fault tolerance for synchronizing a distributed processing system includes a plurality of distributed clock sources. Each clock source may operate as a master clock for synchronizing the operations of the entire system or as a slave to an external clock while remaining available, in a backup capacity, to operate as a master clock in the event of a failure in the previous master clock. A clock selection mechanism is provided in each distributed switch element for selecting the best clock available to each switch element for synchronization. A failure recovery mechanism is provided with fast and automatic recovery in the event of a failure in a master clock. A data extraction mechanism is also provided capable of sampling a bit stream that is not phase-aligned, even in the presence of timing jitter and pulse width distortion, and having provisions for detecting a bit slip.

Abstract: A channel allocation system for selecting the earliest available switch port and time division multiplexed channel for an outgoing transmission in a network of switch elements interconnected by a series of communications paths. An availability table for maintaining the free/busy state of each channel on each switch port in the switch element is provided. Means are additionally provided for limiting the search of the availability table for the earliest available channel to certain desired switch ports and channels.

Abstract: A clocking mechanism with improved fault tolerance for synchronizing a distributed processing system includes a plurality of distributed clock sources. Each clock source may operate as a master clock for synchronizing the operations of the entire system or as a slave to an external clock while remaining available, in a backup capacity, to operate as a master clock in the event of a failure in the previous master clock. A clock selection mechanism is provided in each distributed switch element for selecting the best clock available to each switch element for synchronization. A failure recovery mechanism is provided with fast and automatic recovery in the event of a failure in a master clock. A data extraction mechanism is also provided capable of sampling a bit stream that is not phase-aligned, even in the presence of timing jitter and pulse width distortion, and having provisions for detecting a bit slip.

Abstract: This invention relates to a switch module for use in an asynchronous transfer mode (ATM) system incorporating a shared buffer memory where incoming data cells are stored and subsequently transferred to exit ports. An incoming data cell is stored at a vacant buffer memory address on an interleaved, word-by-word basis and the address is placed in an appropriate priority queue in the appropriate exit port for the data cell. When time is available for transmission from the exit port, the data cell corresponding to the address at the head of the highest priority queue is sent to the exit port and transmitted.

Abstract: A conferencing device and method among terminals in a distributed digital telephone switching system is provided. The telephone switching system has a plurality of switching elements for interconnecting telephone units and telephone lines via communication links. A duplex path is set between each party in the conference and a designated bridge port. The speech from all the parties in the conference is summed and at the bridge port the sum is sent back to all engaged in the conference. As each party receives the sum, it subtracts its own speech data and therefore obtains the speech data from the other parties in the conference.

Abstract: A communication switching system with distributed control processing is provided. The system includes a digital switching network having a modular array of intelligent digital switching elements each having processors and memory to set up communication paths for voice and data between the terminal module processors such as line cards and telephone units. Each addressable location in the system is assigned a logical address code (LAC). When a route is requested, a switch element processor interprets the destination LAC and selects a route through the switch toward the destination with each switch element in the communication path setting a route toward that destination. The switching network provides duplex paths for flexible communication. With such a duplex path speech is directed from a first terminal unit such as a telephone station and a second terminal unit such as a line card into a bridge port which sums the speech data from the two sources.

Abstract: The broadcast system of the switching network provides for the broadcast or multicast of interface switch status broadcasts and interface switch event broadcasts. An interface switch feature processor initiates a broadcast message made up of two bytes of data on a first channel, with particular command codes to identify the type of data contained within the broadcast message, paired with another two bytes of data in the same frame on a second channel. Broadcast messages are sent into the switching network in a non-broadcast manner until they reach the fold point of the switch network. From the fold point the broadcast messages are broadcast on every available broadcast channel directed out of the switch network towards the interface switches.

Abstract: A virtual private line key telephone system is provided. The system includes a console including a plurality of line keys each associated with a party that can be reached via a switched trunk line. A look-up table means associates the line keys with the telephone numbers of the associated parties. A communication path is established from the console to one of the trunk lines. Signals are sent to the central office via the selected trunk line corresponding to the telephone number in the look-up table means associated with a line key that is actuated to place a calls. The telephone number of incoming calls are determined and compared with telephone numbers in the look-up table. Thereafter the line keys which are associated with the incoming calls are determined. The incoming call is coupled to the console when a line key associated with the incoming caller is actuated.

Abstract: A virtual private line key telephone system is provided. The system includes a console including a plurality of line keys each associated with a party that can be reached via a switched trunk line. A look-up table means associates the line keys with the telephone numbers of the associated parties. A communication path is established from the console to one of the trunk lines. Signals are sent to the central office via the selected trunk line corresponding to the telephone number in the look-up table means associated with a line key that is actuated to place a calls. The telephone number of incoming calls are determined and compared with telephone numbers in the look-up table. Thereafter the line keys which are associated with the incoming calls are determined. The incoming call is coupled to the console when a line key associated with the incoming caller is actuated.