Abstract: A combined data compression/error correction system suitable for use in synchronous communication utilizes a data compressor to produce variable rate compressed data from synchronous data. The variable rate compressed data is applied to a FIFO memory which is monitored to determine when the amount of data in the FIFO drops below a predetermined threshold. When it drops below this threshold, an error correction code generator generates a separator character and an error correction code which is appended to the compressed data in the FIFO. Thus, the additional bandwidth created by data compression is used to provide enhancement to the data integrity by providing a variable level of error correction varying in accordance with the free bandwidth generated by the data compressor.

Abstract: A method and apparatus for providing for arbitrary definintion of groups in a data communication network management system. Groups are added, modified, merged, deleted or displayed as desired by the user so that all members of the arbitrarily defined group can be addressed as a group, for example to do a self test and report results. Collectives can be defined as members of the group and the collectives can be unpacked at the time of issuance of a command rather than at the time of creation of the group so that changes to the collective are reflected as changes to the group automatically. Provision is made for creating groups which are commonly desired and significant group configuration activity is logged to either a printer or a file.

Abstract: The present invention is directed toward a method and apparatus in a communications device for mapping a selected group of data bits into a predetermined number of two-dimensional symbols selected from a minimized alphabet of M two-dimensional symbols forming a symbol constellation, with one of the two-dimensional symbols being transmitter during each symbol (i.e., baud) interval. A plurality of symbol mappers in an adaptive communications device use a superframe of bits per baud. Each superframe includes at least two groups of frames, a low bit frame and a high bit frame. The superframe has A) one of these two types of frames uses whole bits per baud and the other uses fractional bits per baud or B) both of these two types of frames will use fractional bits per baud.

Abstract: An apparatus for managing transfer of a packet of information to one of a plurality of ports with each the port having an associated port speed includes a double linked list transmit queue and a plurality of port queues corresponding to the plurality of ports. The packet is read to determine a priority and destination port of the packet. A loadsheding value correlating to the packet's destination port and priority is determined and compared with a measure of the amount of free space in the transmit queue. The packet is loaded into the transmit queue if the loadsheding value is less than or equal to the measure of the amount of free space in the transmit queue. The packet is discarded in the event the loadsheding value is greater than the measure of the amount of free space in the transmit queue.