Photonics Corporation

Other

International Business Machines Corporation

Richard C Allen

John N Piccone

Bernard E Stewart

Stanley L Fickes

Robert J Grady

John W Toor

James E Sacherman

Walter S Johnson

James L Konsevich

Louis R Janis

Gary M Cisneros

Gary N Hughes

Thomas Guthrie Zimmerman

David Lu

Rick L Reagan

Florian Vogt

Charles L Crawshaw

Charles L Cranshaw

Systems and methods for optimizing performance of personal area network (PAN) systems that use electric fields as communication media between PAN transmitters carried by people and PAN receivers mounted on computers to which selective access is sought to be established. Multiple PAN receiver antennae are mounted on a keyboard, such that if a person with a PAN transmitter rests her arms on or near the keyboard, sufficient signal from the transmitter is sensed by one or more of the receiver antennae even though some of the signal is shunted away from the receivers through the arms. Also, a driven shield insulates a PAN receiver from nearby metal objects, e.g., a desk on which the PAN receiver is supported. Moreover, a multiple-electrode PAN transmitter reduces the deleterious effects on the signal from the PAN transmitter that can otherwise be caused by, e.g., loose metal coins that are present in a pocket in which the transmitter is carried. Further, differential receive electrodes prevents undesirable coupling of a PAN transmitted signal to a computer's receiver through a person who has positioned herself between the receiver and the person carrying the PAN transmitter to, for example, gain unauthorized access to the computer.

System and method for optimizing personal area network (PAN) electrostatic communication

A diffuse infrared communication link provides for communication directly between nodes each having a transceiver. A repeater may be present to facilitate communication. Each node is automatically reconfigurable between operation with or without a repeater. When a repeater is present each node automatically ignores any transmission by another node.

Infrared communication repeater architecture

The present invention is for a radiation transmitter which transmits radiation to an illumination spot for forming reflected radiation. The transmitter includes a plurality of radiation transmission sources. Each of the sources transmits to a portion of the illumination spot. The transmitter includes means for alternately activating a portion of the transmission sources to illuminate a portion of the illumination spot for aligning a radiation receiver to receive the reflected radiation. Each resident of network transmits in turn its address and the address of each resident that it recognizes. Once a prospective resident can recognize each resident of the network it announces that it is joining the network and states its new address and the address of each resident it can see. Every resident then amends its list of recognized residents to include the new member.

Infrared network entry permission method and apparatus

Infrared data tranceiver

The present invention is for an illumination transmitter. The transmitter projects a signal onto a planar reflective surface such as the ceiling of an open office environment. The transmitter includes a plurality of illumination sources positioned in a line wherein the line has a predetermined orientation to the planar surface. The illumination sources are preferably infrared LEDs. The transmitter has means for jointly aiming the illumination sources toward a desired location on the planar surface. The location on the planar surface is usually used to allow multiple transmitters coupled to infrared receivers to allow communication between computers in a LAN. The transmitter also includes means for maintaining the predetermined orientation between the planar surface and the line. The orientation is usually parallel to allow transmitters located large distances from the illumination to project a relatively small illumination spot onto the planar surface.

Infrared network transceiver apparatus

An infrared RS 232 communication link protocol is particularly suited for correcting any errors introduced during a transmission of information. The information is transmitted from a transmitting station to a receiving station. Each of the stations has a control counter each of which toggles between a logic 0 and 1. The control counter for the transmitter and the receiver are phase locked so that all errors may be corrected. The receiver echoes each data bit back to the transmitter which compares the echoed data to the transmitted data. If there is a match, the transmission was successful. If there is no match, the data must be retransmitted. A retransmit control character RTXx is sent to indicate that the receiver should discard the previous character and prepare for a retransmission of the character having the error. Under the proper circumstances and if the counters are still phase locked, the receiver then discards the previously stored character and inverts the counter. If the receiver detects that it has received an erroneous character, such as one having multiple or no PPM pulses, the receiver will simply respond with the reject control character REJ. In such a case, the transmitter will respond with an RTXx which causes the receiver to discard the previously stored character and invert the counter.

Link protocol for RS 232 communications

The present invention is for a method for correcting errors in received data during transmission of infrared radiation from a transmitter to a receiver without retransmitting entire packets. The method includes the steps of detecting an error in received data. A negative acknowledgement signal is transmitted from the receiver to the transmitter. A predetermined acknowledgement is transmitted by the transmitter to indicate to the receiver that the negative acknowledgement signal has been received. The data is then retransmitted. The data is transmitted using pulse position modulation. An error is detected by either sensing two pulses within one cycle or sensing no pulses within one cycle. The negative acknowledgement signal comprises transmitting a pulse several positions in duration. The predetermined acknowledgement by the transmitter includes purposely transmitting a cycle containing a known error.

Error correction for infrared data communication

Infrared network entry permission apparatus

The present invention is an apparatus for wireless communications of information between two locations. A transmitter means modulates the information into infrared radiation at a first location. The infrared radiation is transmitted by the transmitter to a reflecting surface along a straight line path which is transparent to the infrared radiation. The infrared radiation is reflected at the reflecting surface forming reflected infrared radiation. A receiver means for receiving the reflected infrared radiation from the reflecting surface is positioned at a second location. The second location and the reflecting surface have a straight line path therebetween which is transparent to the infrared radiation.

Infrared data communications

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Los Gatos, CA, United States of America

Richard C Allen