A system and method for communicating audio data in a packet-based computer network wherein transmission of data packets through the computer network requires variable periods of transmission time. The system comprises: (1) a packet assembly circuit for constructing a data packet from a portion of a stream of digital audio data corresponding to an audio signal, the packet assembly circuit generating a position identifier indicating a temporal position of the portion relative to the stream, inserting the position identifier into the data packet and queuing the data packet for transmission through a backbone of the computer network and (2) a packet disassembly circuit, having a buffer associated therewith, for receiving the data packet from the backbone, the packet disassembly circuit inserting the portion into an absolute location of the buffer, the position identifier determining the location, the portion thereby synchronized with adjacent portions of the stream of digital audio data in the buffer to compensate for the variable periods of transmission time.

System and method for communication of audio data over a packet-based network

A system and method of providing secure communications between two or more hosts connected to a public network, where a secure virtual network (SVN) is established among the two or more hosts.

Method and apparatus for securing communication over public network

A wide area paging system is disclosed in which paging messages input to the system in one local area can be broadcast to a receiver in any other local area without necessarily broadcasting the message in all areas. A local area clearinghouse in each area stores resident subscriber data including current location and receiver serial number. This data is used to transfer messages over a data network to the correct clearinghouse. The system uses a TDM data protocol. The data is encoded and transmitted at a very high rate (e.g., 19,000 baud) in short packets (256 bits/13 milliseconds) via stereo FM sidebands. Receivers are assigned to receive sequentially numbered time slots matching a portion of their address. The addresses of intended receivers are included in the data packets. Battery-powered receivers are deactivated between packets and reactivated in accordance with the sequential time slot number scheme to receive an incoming packet. Messages longer than a packet are segmented and transmitted in two or more packets, linked together by data contained in the packets. A watch pager used in the system employs a wristband antenna which electromagnetically couples to the user's body. The watch pager displays time, telephone numbers and icons representing common types of paging messages.

High capacity protocol with multistation capability

A data communications system and method is provided for sending a data stream of characters in distinct data packets between two units of data terminal equipment connected over communications lines. A modem is connected between each unit of data terminal equipment and the communications lines, and one initializing modem includes a means for changing the packet size of the data which is transmitted. Depending on the response of the receiving modem on whether errors are detected, the size of the data packets is dynamically adjusted. If an error is detected, the data packet size is decreased, and if no error is detected, then the data packet size is increased. If there is no data packet to send, then an idle packet is sent. If the idle packet is received without error, then the packet size of the data packets is increased. If, however, there is an error in the idle packet received, then the size of the data packet will be decreased.

Method and apparatus for effecting efficient transmission of data

A communications system and method utilizes peer-to-peer architecture to provide "quality" real-time communications in a non-guaranteed, packet-based network. Quality real-time communications in a non-guaranteed, packet-based network is achieved by (i) minimizing packet loss, (ii) minimizing latency, and (iii) minimizing the artifacts caused by packet loss. The system distributes control of functionality to the peer communication devices, thereby eliminating the need for a central processor to establish peer-to-peer communications. Each of the peer communication devices has the capability to respond to variations in network loading to provide quality real-time communications.

Communications system having distributed control and real-time bandwidth management

It is efficient to detect a data error, which is produced in a packet switching network, in a range between final users of data. A packet including data for detecting a data error is formed for a data unit made up of a series of data packets sent to a packet mode terminal, and send to the packet mode terminal. A data error is detected by the data for detecting a data error each time the above-mentioned series of data packets are received.

Method and apparatus of packet switching

PURPOSE: To increase the probability for error detection of data, by transmitting a packet added with an error detecting data of the data with a series of data packets addressed to a packet terminal as a unit. CONSTITUTION: A series of packets 50 storing data are transmitted to a packet terminal 11 from a packet terminal 1. Packets 51 storing the data error detecting information are inserted among the packets 50. When the transmission of data is started, the terminal 1 transmits the packets 51 after transmitting a certain number of packets or when there is no packet to be transmitted temporarily. The terminal 11 produces an error check character of the user data from the received user data and in accordance with the procedure arranged with the terminal 1 and then collates the check character with an error check character which is already produced when receiving the packets 51 to perform the checking of an error. COPYRIGHT: (C)1983,JPO&Japio

Setsuo Futamura

Papers

Method and apparatus of packet switching

Error detecting system for exchange of packet