Abstract: A touchframe system includes a plurality of light emitting elements and a plurality of light receiving elements positioned around the perimeter of the display area. Each of the light receiving elements in combination with a plurality of the light emitting elements form a zone of light beam paths. The number and positioning of receivers is sufficient to form a plurality of partially overlapping zone pairs. These zone pairs are arranged relative to the display area such that any touch event lies within at least two zone pairs. A processor monitors each of the zone pairs for blockage of at least one light beam path. Upon such blockage, the processor calculates the location of the touch event associated with the blockage based on the slopes and end points of at least two intersecting blocked light beam paths from a first zone pair and two intersecting blocked light beam paths from a second zone pair.

Abstract: A device for attaching a host or network in data communications with a ring-topology network includes a plurality of contiguous stations which are independently attached in series to the ring-topology network. Each station has the ability to selectively receive data which is not received by the other stations in the device, and each station has the ability to coordinate its receipt of data with the other stations to insure that essentially all data is received by the device.

Abstract: A system for receiving data which is destined for station facilities on a ring-topology network includes a forwarding data channel for establishing data communication between the ring-topology network and the facilities. A station memory for selectively holding data to be transmitted from the facilities over the forwarding data channel and onto the network is also connected to the channel. Additionally, a processor, which generates and continually updates an instruction data frame with address information about the facilities is connected to the station memory. A switch interconnects the forwarding data channel with the ring-topology network to selectively receive data onto the station's channel from the network. A content addressable memory (CAM), which is also connected with the forwarding data channel, receives instruction data frames from the processor, via the station memory over the channel, to control the switch in accordance with address information contained in the instruction data frame.