Abstract: A machine readable binary encoded label having start, data, and stop sections comprising concentric arcuate or linear bars of two different reflectivities.The annular portions or bars are arranged into a coded array such that no more than four adjacent bars are of the same reflectivity type. The start and stop portions are arranged to provide to a scanner sufficient information to determine the scan rate of the scanner regardless of the rate of scan or dimension of bars merely by the scanning passage over the stop or start portion. Scanning circuits for transmitting data information from the data portion of the label to suitable data processing facilities includes a logic arrangement that automatically synchronizes the scanning circuit to the scanner device which may be a machine operating at a substantially constant scan rate or a hand-held wand operated within a wide range of scan rates.This is a division of application Ser. No. 345,322, filed Mar. 27, 1973.