The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 304
1*?Party- SL^fort,)^ 3C*Party v 4*fartf. Fig. 282 respectively for the others—the latter number being for theheaviest ball. Mr Dean has more recently introduced a modification inwhich the bells used are magneto ringers differing from theordinary form in having their armatures fitted on a… … -^U- + Supervisory— 3sF Relay-. falliny fluy~ 4farli,J>ine feZeetUtRuiijiny Jieij^-
Telephone
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