Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems
A 1921 McGraw-Hill engineering treatise by Arthur Bessey Smith and Wilson Lee Campbell explaining automatic and semi-automatic telephone exchanges to switchboard engineers and installers. Its 257 plates are line-drawn circuit diagrams: coils, relays, contact banks and trunk lines rendered as thin hairlines with hand-lettered labels, useful as ready-made grid, node and linework patterns.
