公开(公告)号：DE2353300A1

公开(公告)日：1974-05-09

申请号：DE2353300

申请日：1973-10-24

Applicant: IBM

Inventor： BUCKINGHAM ROBERT LELAND ,  DAVIS JONATHAN BUTLER ,  HERD HAROLD HENRY

IPC: G06K7/10 ,  G06T1/00 ,  G06K7/14

Abstract: What is disclosed is an optical scanner for reading bar codes. The scanner is designed to be held by hand and moved above and across the bar code which is printed on a suitable record substrate. The scanner is composed of a suitable casing containing lamps in the lower portion thereof which illuminate the bar coded record. The illumination is reflected through a unique aperture in the lower surface of the scanner and directed onto a light sensor arrangement such as a photocell. The code marks are in the form of code bars such as black lines separated by white portions. The code consists of "single" code bars and "double" code bars which are, in one embodiment, twice the width of the "single" bars. The aperture arrangement of the scanner is designed according to a scheme such that the resultant signal from the detection of a single bar will always be a known fraction, such as one-half, the amplitude of the signal produced by the detection of a double bar regardless of the changes in speed at which the hand-held scanner is moved across the bar coded record.

公开(公告)号：DE3166666D1

公开(公告)日：1984-11-22

申请号：DE3166666

申请日：1981-03-10

Applicant: IBM

Inventor： DAVIS JONATHAN BUTLER ,  LANIER CHARLES STERLING ,  SZE DANIEL TSI WING

IPC: H04L5/22 ,  G06F13/00 ,  H04L7/00 ,  H04L12/42 ,  H04L12/437 ,  H04L11/16 ,  H04Q5/02 ,  H04J6/00 ,  G06F15/16

Abstract: In a loop-structured communication system interconnecting a plurality of data processors (8 ...13) without central controller, stations (2 ...7) are provided comprising modems (20) which can start loop operation and achieve synchronous frame transmission around the loop through all participating stations. In an initialization procedure after system start or after loss of frame synchronization on the loop, modems select a temporary master station. The temporary master will adapt total loop delay to be an integer multiple of the basic frame period, and will transmit available frames. All active modems adapt their timing to the circulating stream of frames until the whole loop and all participating stations are synchronized. Synchronization conditions are continuously monitored in all stations to start resynchronization or initialization procedures if necessary. In a specific arrangement, the location of a loop failure which prevents establishment of synchronization can be determined. All initialization and synchronization operations are handled by the modems without participation by other functional units or by the host processing system of any station.