Abstract: The terminal device has a network transceiver and a processor having a first program to cause the processor to transmit a packet of data using the network transceiver in accordance with a data transmission protocol. The first program begins transmission of a packet by sending data to a transmit signal input of the network transceiver in accordance with the protocol. At a circuit level associated with the network transceiver, a received signal in the transceiver is detected at a time of sending data to the transmit signal input. In response to this detection, transmission of the packet is prevented.

Abstract: The network uses detection of collision based on start bit transmission under poor transmission line conditions and with a large number of devices on the network. Data throughput is double that of CSMA-CA for the same network conditions. Some network devices operate with dual protocols. The network device has a network transceiver and a processor that uses an interrupt to detect transmission on the line for start bit detection.

Abstract: A security system user interface comprising a graphical display, a communication link, a memory, and a display controller. The communication link receives detector unit status data from detector units located at selected location on the premises protected by the security system. The memory stores floor plan diagram data and detector unit location data. Finally, the display controller generates a modified view of at least a portion of the floor plan diagram data in accordance with the detector unit status data to indicate the status data, and displaying the modified view on the graphical display. The invention also provides, in combination, a user interface and a user programming interface for transmitting the floor plan diagram data and the detector unit location data to the communications interface of the user interface.