Multi-terminal computer system with dual communication channels

A communication system, comprising:

• a computer;
• a plurality of terminals disposed at remote, spaced locations relative to the computer;
• a continuous, elongated segment of a signal conductor running along a path extending in proximity to the computer and to each of the terminals;
• signal conducting connections extending between the signal conductor and each of the terminals;
• a primary transmitter connected to one end of the signal conductor and providing output to the signal conductor on a first band-width;
• a secondary transmitter connected to the opposite end of the signal conductor and providing output to the signal conductor on a secondary band-width, which differs from the first band-width;
• output connections from the computer to both the primary and secondary transmitters;
• a primary transmitter signal sensor connected to the signal conductor adjacent to the end connected to the secondary transmitter;
• a secondary transmitter control circuit connected to the output of the last said sensor and operative to energize the secondary transmitter when the sensor does not detect a primary transmitter signal;
• and pairs of first and second band-width receivers associated with each terminal;
• whereby signals from the computer are normally transmitted to the terminals employing the primary transmitter and in the event of failure of the primary transmitter or of interruption of the signal conductor the secondary transmitter is energized and provides output to the signal conductor.