Abstract: Guard-time elimination in a time-division multiplexed, active star-coupled, local area, half-duplex mode, synchronous communications network. Guard time between data packets arriving at the central node of the network is eliminated by adjusting the word slot timing at each terminal such that the data arriving at the central node from each terminal in the network is properly phased with data received from other terminals in the network. The terminal initiallization process required for this timing adjustment is accomplished without disruption of other traffic concurrently being processed through the network.

Abstract: A wavelength division multiplexed fiber-optic communication system employs a pair of terminal stations, at opposite ends of the fiber-optic link, with the base configuration of each terminal station being the same. In each station a selective coupling arrangement is provided between the source or transmitter devices as well as the receiver devices and the single optical fiber over which the transmission are to take place so as to effectively make the terminals interchangeable. For achieving this purpose, each terminal station is comprised of a transmitter or source arrangement that is capable of generating a plurality of wavelengths. Similarly, each terminal station includes a receiver or detector which is capable of detecting the plurality of wavelengths that are selectively available for transmission or generated by the transmitter or source.

Abstract: An auxiliary channel, for example, an engineering orderwire, is derived on n existing time-division multiplex carrier system by modulating the pulse repetition rate of the digital bitstream. The modulating signal itself may be an analog or a digital signal. The modulator and demodulator both include a first-in, first-out shift register acting as a buffer, and the desired modulation is effected by varying the rate at which the digital information is fed out of the FIFO buffer at the transmitting end of the carrier system.