American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 601
op, but a more prolonged signal, such as a dash, will. Itwill, therefore, be plain that if ordinary signals, such as may be used to note the ar-rival of an officer at a box, are composed exclusively of * dots, the ■ alarm in thecentral office will not ring ; while, if a special signal is made up of… … As has been intimated, means are provided in the central office for calling up anofficer on his arrival at the patrol box in the absence of the attendant at the centraloffice. This consists of an arrangement of the gearing in the register box, whereby awheel M, at the recurrence of each signal, is…
Telegraph
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
