Abstract: Systems and methods of switching between internal and external display adapters in a portable computer system are described. In one aspect, a graphics controller is configured to convert video output signals that are received from a processing unit into locally-generated video control signals and to selectively transmit to a local video display the video control signals that are generated locally or video control signals that are received from a docking station interface. In this way, when undocked, a portable computer unit may drive the local video display with a local adapter that is optimized for mobile usage (e.g., enhanced power management) and, when docked, the portable computer unit may drive the local video display with a higher performance external display adapter, which typically is not constrained by power management considerations.

Abstract: A light transistor system, including an image transistor, and a coolant passageway extending through the image transistor. The image transistor has a liquid crystal modulator, configured to amplify a low-power light signal using amplification energy from a higher-power light source, such as a laser or arc lamp. The coolant passageway is configured to receive a flow of coolant therethrough, to allow cooling of the image transistor to prevent damage to it from the higher-power light source.

Abstract: A wireless network and associated method for providing continuous communication service for a mobile unit as it roams within a virtual wireless network. The virtual network includes home and foreign access controllers and a virtual network manager (VN manager). The VN manager is used to maintain a VN configuration record that includes all active access controllers within virtual network and to disseminate said VN configuration record to all active access controllers. A tunneling data communication connection is established between all active access controllers including home and foreign access controllers. When a mobile unit first connects to home access controller and then roams to foreign access controller, communication data is transmitted between the mobile unit and the foreign access controller to provide continuous data communication on the basis of the characteristics defined by the virtual networking services while simultaneously preserving the IP configuration of mobile unit on the network.

Abstract: A method for preventing network address spoofing within a wireless local area network (LAN) that includes an access controller and first and second radio units. The method first associates a first mobile unit to the first radio unit, determines the network address of the first mobile unit and maintains a connectivity record that contains the network address and identifies that the first radio unit has been associated with. If a second mobile unit requests association with the second radio unit then the network address of the second mobile unit is determined. If the network address of the second mobile unit is the same as the network address of the first mobile unit then the connectivity record associated with the network address of said first and second mobile units is checked. If the connectivity record indicates an association with the first radio unit then an anti-spoofing protocol is executed.

Abstract: A wireless network for supporting mobile unit traffic segmentation for a plurality of mobile units to associate each mobile unit with virtual networking services (VNS). The wireless network includes a plurality of radio units and access controllers. Each radio unit is adapted to initiate the connection of a mobile unit to the network by transmitting and receiving communication data to and from the mobile unit. Each access controller is adapted to receive communication data from each radio unit during the connection of a mobile unit. Based on the communication data transmitted to the radio unit during connection of the mobile unit, access controller is able to discover VNS factors for the mobile unit communication session and to establish a communication session based on the VNS factors discovered during the connection process such that the mobile unit is connected to the network on the basis of the characteristics defined by the virtual networking services.

Abstract: A method and system are provided for protecting an analog video signal sent from a video signal source to a video display enabled to receive a protected video signal. The method includes sending a string of bit values in an encrypted format from the video display to the video signal source. The string of bit values is received in the video signal source and decrypted. The string of bit values is then divided into multi-bit segments in both the video display and the video signal source. A common multi-bit segment in the string of bit values is selected for both the video display and video signal source. A plurality of analog video channels is then sent in a switched order from the video signal source to the video display based on the common multi-bit segment. The plurality of analog video channels is finally decoded in the video display using the common multi-bit segment to decode the switched order.

Abstract: A method and system is provided for transferring data between a host and a video display through a video interface. The method includes the step of providing a horizontal sync line between the host and the video display with time intervals that are reserved for a horizontal sync signal. Another step is signaling to the host that the video display is able to participate in bidirectional data communications using the horizontal sync line. A further step is transferring data between the host and video display on the horizontal sync line during time intervals that are not reserved for the horizontal sync signal.

Abstract: A method is provided for accurately sampling pixels in a fixed-format display, which is connected to a host computer through an analog video display adapter. The method comprises the step of confirming that the fixed-format display is able to receive a pixel clock signal from the analog video display adapter. Another step is sending the pixel clock signal across an analog video sync line so that synchronization data and the pixel clock signal will be contained on the analog video sync line. An additional step is receiving the pixel clock signal in the fixed-format display. A further step is applying the pixel clock signal in the fixed-format display to sample pixels.

Abstract: A method is taught for providing a reference video signal to a video display through a video interface from a video display adapter for a host computer. The method includes the step of providing a horizontal sync line to carry a horizontal sync signal that occupies pre-defined time intervals as a representation of a horizontal sync pulse. Another step is signaling to the video display adapter that a reference amplitude pulse will be sent on a video data line. A further step is sending the reference amplitude pulse on a video data line during the pre-determined time intervals when the horizontal sync signal occupies the horizontal sync line.

Abstract: A light transistor system, including an image transistor, and a coolant passageway extending through the image transistor. The image transistor has a liquid crystal modulator, configured to amplify a low-power light signal using amplification energy from a higher-power light source, such as a laser or arc lamp. The coolant passageway is configured to receive a flow of coolant therethrough, to allow cooling of the image transistor to prevent damage to it from the higher-power light source.

Abstract: Systems and methods of switching between internal and external display adapters in a portable computer system are described. In one aspect, a graphics controller is configured to convert video output signals that are received from a processing unit into locally-generated video control signals and to selectively transmit to a local video display the video control signals that are generated locally or video control signals that are received from a docking station interface. In this way, when undocked, a portable computer unit may drive the local video display with a local adapter that is optimized for mobile usage (e.g., enhanced power management) and, when docked, the portable computer unit may drive the local video display with a higher performance external display adapter, which typically is not constrained by power management considerations.

Abstract: A bi-directional high speed video data transmission system. A transmitter transmits an encoded video data stream across a data pair to a receiver by switching a DC current, via a pair of transistors, across the two data lines comprising the data pair. As the current varies on the data lines, so too does the voltage. The receiver decodes the serial video data stream back into its component parts so that the video data may be displayed by an appropriate display device. A pair of summing resistors adds the AC currents seen across the data lines to reconstruct the original DC current as a DC return current. The DC return current may be used to drive a return transmitter located on the original receiving side in order to send video data to the original transmitting side of the bi-directional video data transmission system.

Abstract: The protocol layers of a wireless communication protocol (such as Bluetooth) are divided between an access point device and a back end device such that the access point device implements a lower protocol layer of the wireless communication protocol and the back end device implements upper protocol layers of the wireless communication protocol. This allows the access point device to be small, simple, and inexpensive. The back end device implements various state-based functions that are processor and memory intensive.

Abstract: An apparatus for converting a video input signal representing an image from a first format to a prescribed second format. The apparatus comprises the following elements: a sync separator (30) for extracting a synchronization (sync) signal from the video input signal; a section (32, 34, 36, 40) for generating a sample clock signal on the basis of the sync signal and the said prescribed format; a sampling section including A/D convertors (18a, 18b, 18c) for sampling the video input signal in accordance with the sample clock signal to obtain a prescribed number of samples per line of the image; a section (20a, 20b, 20c, 22) for combining the samples of at least two different lines to obtain a prescribed number of new lines each of which comprises the said prescribed number of samples per line; and a filtering section (17a, 17b, 17c) for filtering the video input signal so as to effectively horizontally average each line of the image.

Abstract: A light pen system in accordance with the present invention comprises (a) detecting means for detecting horizontal and vertical sync signals for controlling a raster-scan display; (b) line counter means, coupled to the detecting means and responsive to the horizontal sync signals, for providing a line count corresponding to the vertical position of the beam; and (c) pixel counter means, coupled to the detecting means, for providing a pixel count corresponding to the horizontal position of the beam.

Abstract: This invention relates to personal computers, and more particularly to personal computer power supplies for supplying electrical power to electrically operated components which manipulate or store digital data. The power supply has a controllable component for responding to the presence and absence of a low voltage direct current electrical signal by enabling and disabling the supply of electrical power to the data processing and storage components, and a signal generator circuit operatively connected with the controllable component and with an alternating current electrical main supply for controllably deriving from the main supply a low voltage direct current signal for delivery to the controllable component, whereby a user of the microcomputer may control energization of the electrically powered data processing and storage components by controlling the application of the low voltage direct current signal from the signal generator circuit to the controllable component.