27. Name the different parts which comprise a telephone set.
28. What is a magneto telephone?
29. Make diagram of the circuit of a series magneto set with receiver on the hook and explain how the different currents are flowing.
30. Show diagram of the Stromberg-Carlson magneto desk telephone circuit and describe its working.
31. Give sketch of the Stromberg-Carlson common-battery wall set circuit.
32. Describe briefly the microtelephone set.
33. Make sketch of the Monarch common-battery wall set.
REVIEW QUESTIONS
ON THE SUBJECT OF TELEPHONY
PAGES 227--286
1. What is a party line?
2. What is usually understood by private lines?
3. What problem is there to overcome in connection with party lines?
4. State the two general cla.s.ses of party-line systems.
5. Point out the defects of the series system.
6. Make sketch of a metallic bridging line and show the circuit for the voice currents.
7. What is a signal code?
8. Give cla.s.sification of selective party-line systems with short definitions.
9. Describe the principle of selection by polarity and make sketch ill.u.s.trating this principle.
10. Make diagram of the circuit of a four-party station with relay.
11. Describe the process of tuning in the harmonic system.
12. What is the difference between the under-tune and in-tune systems?
13. Sketch circuit of Kellogg"s harmonic system.
14. Ill.u.s.trate the principle of a broken-line system by a sketch.
15. In what particulars does the party-line system in rural districts differ from that within urban limits?
16. Describe and sketch Pool"s lock-out system.
17. Make diagram of the K.B. lock-out system.
18. What is the object of the ratchet in this system?
19. Make diagram of simplified circuits of Roberts system.
20. Sketch and describe Roberts latching key and connections.
21. Sketch circuits of bridging station for non-selective party line.
22. How would you arrange the signal code for six stations on a non-selective party line?
23. What is the limit of number of stations on a non-selective party line under ordinary circ.u.mstances?
24. State the objections against the party polarity system as shown in Fig. 172.
25. What are the advantages of the harmonic party-line system?
26. To how many frequencies is the harmonic system usually limited?
27. What can you say about the commercial success of the step-by-step method?
28. State the principles of a lock-out party line.
29. For what purpose is a condenser placed in the receiver circuit of each station in the K.B. lock-out system?
30. How are the selecting relays in Roberts line restored to their normal position after a conversation is finished?
31. What are the objections against the Roberts system?
REVIEW QUESTIONS
ON THE SUBJECT OF TELEPHONY
PAGES 287--315
1. What are electrical hazards?