P
Phantom circuit321Pilot signals17Plug-seat switch38Pole changers for harmonic ringing231Power plants227auxiliary signaling currents233currents employed227alternating current227direct current227operator's transmitter supply228power plant circuit248power switchboard246meters246protective devices248switches246primary sources234charging from direct-current mains234charging dynamos235mercury-arc rectifiers236rotary converters234provision against breakdown237capacity of power units238duplicate charging machines238duplicate primary sources238duplicate ringing machines238ringing-current supply229magneto generators229pole changers229ringing dynamos232storage battery239initial charge241installation240low cells244operation242overcharge243pilot cell243regular charge244replacing batteries245sediment245types227common-battery systems228magneto systems228Power switchboard246Private-branch exchanges271with automatic offices278secrecy279battery supply279circuits, key-type board276definitions271desirable features281functions of the private-branch exchange operator272marking of apparatus281private-branch switchboards273common-battery type273cord type275key type275magneto type273ringing current280supervision of private-branch connections277
R
Relays28Rotary connector202
S
Selecting switches175Selector175Simplex circuits324Storage battery239Storage cell240Stromberg-Carlson multiple board96Strowger automatic system143Subscribers' board259-261Switchboard assembly31
T
Tableautomanual system time data225automatic systems, messages per trunk in305calling rates302long-distance groups, messages per trunk in305manual system, messages per trunk in304out-trunking, effect of, on operator's capacity303subscribers' waiting time226Telephone traffic298importance of traffic study300methods of traffic study301observation of service308quality of service305accuracy and promptness307answering time306busy and don't answer calls307courtesy and form307disconnecting time306enunciation308team work308rates of calling300representative traffic data302calling rates302operators' loads302toll traffic304trunk efficiency303trunking factor303traffic variations298busy hour ratio299unit of traffic298Telephone train dispatching333advantages335apparatus338Cummings-Wray selector342dispatcher's transmitter343Gill selector341portable train sets345siding telephones345waystation telephones344Western Electric selector338blocking sets355causes of its introduction334Cummings-Wray circuits350on electric railways356Gill circuits349railroad conditions337rapid growth333test boards353transmitting orders337waystation circuits348Western Electric circuits347Telephone train-dispatching circuitCummings-Wray350Gill349waystation348Western Electric347Test boards353Transfer switchboard34field of usefulness41handling transfers38limitations40plug-seat switch38transfer lines35jack-ended trunk35plug-ended trunk37Trunking in multi-office systems109classification112one-way trunks103two-way trunks112Kellogg trunk circuits125necessity for exchanges109Western Electric trunk circuits116
W
Warner pole changer230Waystation telephones344Western Electricmechanical signal27selector338trunk circuits116
Spelling variants where it wasn't possible to determine the author's intent were left as is. These include: "clockwork" and "clock-work;" "doorkeeper" and "door-keeper;" "interrelation" and "inter-relation;" "multicyclic" and "multi-cyclic;" "redesign" and "re-design," along with derivatives.
Added closing double quote in Steinmetz entry in list of authorities: "Theoretical Elements of Electrical Engineering."
Changed "switch-hook" to "switch hook" on page 88: "the subscriber's switch hook."
Page 107 says there is room for 300 banks of 100 multiple jacks, but then says this allows for 3,000 multiple jacks in all, rather than 30,000. Based on the figure, 300 banks should be 30 banks, which would correct the arithmetic. However, I did not change this.
Changed "bi-paths" to "by-paths" on page 185: "circuits or by-paths."
Changed "appararus" to "apparatus" on page 209: "The sectional apparatus."
Changed "two number" to "two-number" on page 312: "the two-number calls are ticketed."
On page 333, a paragraph begins with "It has been only within the past three few." Perhaps the author meant "It has been only within the past three years" or "It has been only within the past few years." But since I didn't know, I left is as is.
Changed "them ain" to "the main" on page 333: "on the main line."
Changed "weatherproof" to "weather-proof" on page 357: "iron weather-proof sets."
Changed "interoffice" to "inter-office" three times on page 364, to match the spelling in the body of the document: "meant by inter-office trunking;" "inter-office connection system;" "of the inter-office connection."
Changed "break-down" to "breakdown" on page 367: "provision against breakdown."
Changed "way-station" to "waystation" twice on page 372: "with a waystation set;" and "a waystation on a block wire."
Changed "way stations" to "waystations" on page 375, in the entry for Long-distance switching.
Each page of the Index repeated this text: "Note.—For page numbers see foot of pages." They were removed.