公开(公告)号：US3665406A

公开(公告)日：1972-05-23

申请号：US3665406D

申请日：1970-04-13

Applicant: BUNKER RAMO

Inventor： GALLAGHER FRANK WILLIAM ,  CASEY RICHARD C

IPC: G06F13/24 ,  G06F9/18

CPC classification number: G06F13/24

Abstract: A device for generating polling messages to a plurality of addressable stations. A central processing unit (CPU) generates a polling table which is stored in an external automatic polling device. The polling device detects an address in the polling table and generates a polling message to the indicated station. The device receives responses to polling messages and tests to determine if they are positive or negative. A negative response causes a polling message to be sent to the station indicated by the next address in the polling table. A positive response causes an interrupt to the CPU which then receives the reply message. Interrupts to the CPU may also be generated when there is no response to a polling message, when there is an error response, or when the end of the polling table is reached.