Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 242
eeking a connection will seize the idleorder-wire trunk. The busy signal is closed during the operation of themaster switch mechanism also. The apparatus may be used either with, or without, what is called theposition blocking feature, as desired. That is, it may be arranged to dis-tribute the load… … Fig. 196.- Position 6 to last Po. To Pilot Control. Key Postn4 rc=~ These Keys are thrown . V=^-? & &^ ■? J_ when corresponding position _|_ g-a^> < ~T~ /s occupied —]-^>-4 ^£ ---\BusyPlfotLamp \ + on center Panel \ j; / per Position § * These Keys are thrown when correspond-ing…
Telephone
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-354-223.webp)
