A video teleconferencing method and apparatus for computer workstations connected by a digital data network includes a transmission source portion for a local workstation to send audio and video teleconference data across the network to one or more remote workstations, and, a receiver for the local workstation to receive audio and video teleconference data back from the remote workstations. The local workstation sends teleconference data to each of the remote workstations over a variable bandwidth digital data connection, and each of the remote workstations returns teleconference data back to the local workstation over another variable bandwidth digital data connection. The transmission source portion includes a master software process executing on the local workstation, and the receiver includes a slave software process executing the remote workstation. The master process of a local workstation causes execution of a slave process on a remote workstation for receiving video teleconference data from the local workstation. An audio data transmitter for sends an audio data stream to the remote workstation such that the audio data can be reconstructed into a continuous audio signal. A video transmitter sends video data so that each frame of video data to be sent is inserted into the audio data stream without affecting the continuity of the reconstructed audio signal at the remote workstation.

Video teleconferencing for networked workstations

A serial intelligent cell (SIC) and a connection topology for local area networks using Electrically-conducting media. A local area network can be configured from a plurality of SIC's interconnected so that all communications between two adjacent SIC's is both point-to-point and bidirectional. Each SIC can be connected to one or more other SIC's to allow redundant communication paths. Communications in different areas of a SIC network are independent of one another, so that, unlike current bus topology and star topology, there is no fundamental limit on the size or extent of a SIC network. Each SIC can optionally be connected to one or more data terminals, computers, telephones, sensors, actuators, etc., to facilitate interconnectivity among such devices. Networks according to the present invention can be configured for a variety of applications, including a local telephone system, remote computer bus extender, multiplexers, PABX/PBX functionality, security systems, and local broadcasting services. The network can use dedicated wiring, as well as existing wiring as the in-house telephone or electrical wiring.

Local area network of serial intelligent cells

A device, network and method wherein a standard wireless modem is coupled to wiring for carrying a wireless baseband signal that may be OFDM based, and may be directly generated by the wireless IF modem, or extracted from the modem RF signal. The wiring may be a building utility wiring, such as telephone, AC power or CATV wiring. The baseband signal is carried simultaneously with the utility service signal over the utility wiring using Frequency Division Multiplexing. The device may be enclosed with a data unit, a standalone dedicated enclosure, within an outlet or as a plug-in outlet adapter. Data units may couple the device by a wiring port such as standard data connector, or via wireless connection. The device may be locally powered or via a power signal carried over the wiring. This abstract is not intended to limit or construe the scope of the claims.

System and method for carrying a wireless based signal over wiring

A telecommunication system provides voice and data communications over a conventional telephone line that can be dynamically switched from voice mode to data mode during a single conversation. Each station includes a telephone for voice communications and bypass relay means for selectively connecting the telephone to the telephone line in voice mode and disconnecting the telephone while operating in data mode. Prior to transmitting data, the originating station first transmits a start signal over the telephone line that includes a rate signal indicating one of the several possible data transmission rates. If a station detects a start signal transmitted by a remote station, a microcontroller directs the bypass relay means and modem to automatically switch from voice mode to data mode in preparation for receiving data from the originating station.

Telecommunication display system

A video transmission system for facilitating transmission of video and control signals, particularly infrared remote control signals, between different locations in a residence using existing telephone wiring. Simultaneous transmission of signals of both types over active telephone lines is possible without interference with telephone communications. Transmission succeeds without requiring special treatement of the video signals beyond RF conversion, despite signal attenuation inherent in transmission over the telephone line media. Two or more video sources may be tied into the system, and selected as desired. Remote control signals generated in one room may be utilized without requiring a clear line of sight between the remote control device and the receiver.

Video transmission and control system utilizing internal telephone lines

An improved video phone which transmits a source image over a standard telephone line in conjunction with audio voice signals is disclosed. The unique initialization protocol allows asynchronous transmission with its short format. The protocol format provides for a hardware preamble for synchronizing a receiver clock, a software preamble for identifying the video image and disabling the audio, automatic gain control adjustment data and amplitude calibration data. The audio portion is disabled by coupling a capacitor across the telephone to effectively short the telephone. The telephone is placed across the bridge circuit which is provided with switches to balance the bridge in both the telephone audio and the video modes. The transmitted as well as the received signal are passed through the same delay equalization circuit, so that half the delay equalization is done before transmission, with the remaining half being done after reception. The use of a multiplexer and demultiplexer allows the same circuit to be used. The digital signals are level shifted from 5 volts to 10 volts prior to being converted into analog, and then are level shifted down again to reduce the effects of DC offset. The digital and analog voltage supplies are coupled together with a resistor and diode, and a capacitor is coupled between the analog supply and ground to combine the reset and voltage supply functions. An RC circuit providing 180° of phase shift is coupled to the crystal oscillator to produce a clock which is locked into the series resonant frequency of the oscillator. The camera and the rest of the circuitry is turned on and off by a switch coupled to panel which can be slid in front of the camera, thus providing for the automatic protection of the camera lens when the system is switched off.

Conversational video phone

A still picture picturephone communication system for transmitting and receiving a still picture over a telephone circuit including a handshaking process wherein prior to still picture transmission, identification code data indicating a function of picturephone set is transmitted and received, and decision is made as to whether the still picture is being transmitted or not, wherein a designation code of a desired response waiting time within an identification code data used at the time of handshaking is formed, and the response is delayed by a period of time corresponding to the response waiting time, a still picture data is directly transmitted and received without handshaking, a character data including character information and the like is transmitted and received, manipurating a picturephone set on one party can be made a picturephone set on the other party to transmit a picture data therefrom, furthermore, the picture sent from the called party can be transferred to a third party.

James Scott Mackley

Papers

Conversational video phone

Still picture picturephone communication system