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?
2. When is the lightning hazard least?
3. What actions can electricity produce? Which involves the greater hazard to the value of property?