Abstract: An electronic failure detector includes an electronic processor having processor inputs and processor outputs, a memory connected to one of the inputs, a logic circuit having logic circuit inputs and logic circuit outputs, the logic circuit inputs and logic circuit outputs being connected to others of the processor inputs, and instructions, stored within the non-volatile memory, for causing the processor to perform a logic check of the logic circuit and to generate a first signal on the processor output if said logic check is true, and to generate a second signal on the processor output if said logic check is false.

Abstract: A method and apparatus for dispatching elevator cars to hall calls in a system where there are two types of elevator controllers (12, 14) in operation, one (12) of which operates using relay logic. The calls are stored in a relay logic memory common to both elevator controllers (12, 14). A first controller reads the call information directly from the memory (18); the second controller reads the memory through a cross cancellation device (10) which multiplexes the information from the memory so that the calls are provided on a serial link (32) to the second controller (14). The second controller (14) is programmed to respond to calls which the first controller (12) has not answered.