13.  What are ringing and listening keys?

14.  Show symbols for ringing and listening keys.

15.  State the parts of which a cord equipment consists.

16.  Show step by step the various operations of a telephone system wherein the lines center in a magneto switchboard.  Make all the necessary diagrams and give brief descriptions to show that you understand each operation.

17.  On what principle does a drop with night-alarm contact operate?

18.  What is the advantage of associating jacks and drops?

19.  Describe the mechanical restoration as employed in the Miller drop and jack.

20.  Describe the electrical restoration of drop shutters as manufactured by the Western Electric Company.

21.  What complications arise in ringing of party lines and how are they overcome?

22.  Give diagram of the complete circuit of a simple magneto switchboard.

23.  Sketch night-alarm circuit with relay.

24.  What is a convertible cord circuit?

25.  State what disadvantages may be encountered under certain conditions with a bridging drop-cord circuit.

26.  Are lamps in cord circuits to be advocated on magneto switchboards?

27.  What is the function of the cabinet?

28.  Give cross-section of upright switchboard as used in the magneto system.

29.  What is the purpose of a sectional switchboard?

30.  Give a short description of the essential parts of a sectional switchboard.

INDEX

INDEX

The page numbers of this volume will be found at the bottom of the pages; the numbers at the top refer only to the section.

A

Acousticon transmitter
Acoustics
    characteristics of sound
        loudness
        pitch
        timbre
    human ear
    human voice
    propagation of sound
Air-gap vs. fuse arresters
Amalgamated zincs
Arrester separators
Audible signals
    magneto bell
    telegraph sounder
    telephone receiver
    vibrating bell
Automatic Electric Company
    direct-current receiver
    transmitter
Automatic shunt

B

Bar electromagnet
Battery bell
Battery symbols
Blake single electrode
Brazed bell
Broken-back ringer
Broken-line method of selective signaling

C

Capacity reactance
Carbon
    adaptability
    limitations
    preparation of
    superiority
Carbon air-gap arrester
Carbon-block arrester
Carrying capacity of transmitter
Central-office protectors
Characteristics of sound
    loudness