Modular operational elevator control system

A control system for controlling communication between passengers and an elevator controller including fixtures for providing passenger request signals in response to passenger service requests and for providing displays to the passengers indicative of status signals from the controller, and means for communicating the passenger request signals from the fixtures to the controller and for communicating the status signals from the controller to the fixtures, comprising:

• a transmission line;
• a portion of the controller dedicated to the control system for controlling communication between the passengers and the remainder of the controller for providing clock pulses on the transmission line to mark time slots in a transceive cycle of a time-division, half-duplex multiplex protocol;
• and
• a master station, connected between the portion of the controller and the transmission line, comprising:
• first counter means for providing first receive cue signals during assigned time slots in response to the clock pulses and for providing first transmit cue signals during assigned other time slots in response to the clock pulses;
• first output switch means for providing the passenger request signals from the transmission line in serial format to the portion of the controller on first parallel output lines in a system receive mode in response to the first receive signals according to the multiplex protocol;
• and
• first input switch means for providing the status signals from the portion of the controller on first parallel input lines to the transmission line in serial format in a system transmit mode in response to the first transmit signals according to the multiplex protocol;
• remote stations, each connected between the fixtures and the transmission line and comprising:
• second counter means for providing second receive cue signals during an assigned time slot in respose to the clock pulses and for providing second transmit cue signals during an assigned other time slot in response to the clock pulses;
• second input switch means for providing the passenger request signals from the fixtures on second parallel input lines to the transmission line in serial format in the system receive mode in response to the second receive cue signals according to the multiplex protocol;
• and
• second output switch means for providing the status signals from the transmission line in serial format to the fixtures on second parallel output lines in the system transmit mode in response to the second transmit cue signals according to the multiplex protocol.