Before the widespread adoption of common-battery systems, what type of system relied on a magneto generator at each subscriber’s station to generate ringing current?
- Automatic system
- Common-battery system
- Magneto system
- Strowger system
Correct Answer: Magneto system
Correct Answer Explanation: Magneto systems relied on a magneto generator at each subscriber’s station to produce ringing current, requiring local batteries for power. Common-battery systems eliminated the need for individual magneto generators and local batteries, centralizing power at the exchange.
What component, often found in multiple switchboards, served as a crucial feature to prevent double connections and ensure accurate busy tests?
- The line switch
- The cut-off relay
- The pilot lamp
- The busy test
Correct Answer: The busy test
Correct Answer Explanation: The busy test was a crucial feature in multiple switchboards, preventing double connections by ensuring that a single line couldn’t be connected to multiple callers simultaneously. It allowed the operator to determine if a line was already in use and avoid connecting another caller.
What significant advantage did common-battery systems offer over magneto systems in terms of maintenance, signaling, and overall efficiency?
- They allowed for the use of automatic switching mechanisms.
- They eliminated the need for local batteries at each subscriber’s station.
- They could handle a larger volume of traffic.
- They were more reliable in rural areas.
Correct Answer: They eliminated the need for local batteries at each subscriber’s station.
Correct Answer Explanation: Common-battery systems eliminated the need for local batteries at each subscriber’s station, simplifying subscriber instruments, reducing maintenance requirements, and making telephone service more convenient. This centralized power approach contributed to greater efficiency and reliability.
What device, found in automatic systems, allowed for inter-office trunking over two-wire lines, enabling communication between offices without the need for a separate third wire?
- The master switch
- The bridge cut-off relay
- The line switch
- The trunk repeater
Correct Answer: The trunk repeater
Correct Answer Explanation: The trunk repeater allowed for inter-office trunking over two-wire lines in automatic systems, eliminating the need for a third wire for communication between exchanges. This was a crucial advancement in optimizing communication pathways and reducing infrastructure requirements.
What specialized telephone system, typically manually operated, provided local communication within a business and connections to the public network?
- Automatic systems
- Phantom circuits
- Private branch exchanges
- Intercommunicating systems
Correct Answer: Private branch exchanges
Correct Answer Explanation: Private branch exchanges (PBX) served as a specialized telephone system within a business, handling internal calls and connecting to the public network. These systems often featured an operator for call management, offering flexibility for various communication needs.
What is the name of the widely used automatic system that is characterized by its step-by-step switching mechanism controlled by impulses from the subscriber’s dial?
- The Lorimer system
- The Strowger system
- The automanual system
- The Sabin-Hampton system
Correct Answer: The Strowger system
Correct Answer Explanation: The Strowger system, developed by Almon B. Strowger, was a dominant automatic system in the early 20th century. Its step-by-step switching mechanism, controlled by impulses from the subscriber’s dial, provided a reliable and efficient method for routing calls.
What type of circuit, often used for communication between train stations, could extend for up to 300 miles and serve up to 65 stations?
- Phantom circuits
- Simplex circuits
- Intercommunicating circuits
- Telephone train dispatching circuits
Correct Answer: Telephone train dispatching circuits
Correct Answer Explanation: Telephone train dispatching circuits were specifically designed for communication between train stations, extending over long distances to manage train operations effectively. These circuits used specialized selectors and signaling mechanisms for rapid and reliable communication.
What is the typical voltage of a sending battery for train dispatching circuits, determined by the line’s length and number of stations?
- 10 to 30 volts
- 100 to 300 volts
- 500 to 1000 volts
- 1000 to 2000 volts
Correct Answer: 100 to 300 volts
Correct Answer Explanation: The voltage of a sending battery for train dispatching circuits typically ranged from 100 to 300 volts, adjusted based on the length of the line and the number of stations served. This ensured efficient signal transmission over these long-distance circuits.
What type of device, often used in telephone systems for ringing bells, converted direct current into alternating current?
- The mercury-arc rectifier
- The Warner pole changer
- The iron-wire ballast
- The plug-seat switch
Correct Answer: The Warner pole changer
Correct Answer Explanation: The Warner pole changer was a device used in telephone systems to convert direct current into alternating current, primarily for ringing bells. This transformation was essential for operating the mechanical bells used in older telephone systems.
What device, used in early telephone systems, helped to regulate the current flow to a line lamp, ensuring proper illumination regardless of the line’s resistance?
- The mercury-arc rectifier
- The Warner pole changer
- The iron-wire ballast
- The plug-seat switch
Correct Answer: The iron-wire ballast
Correct Answer Explanation: The iron-wire ballast was a crucial component in early telephone systems, serving as a current regulator for line lamps. It prevented the lamp from being overloaded or underpowered, ensuring consistent brightness even with varying line resistances.
What type of circuit, discussed in the Cyclopedia, allowed for simultaneous telephone and telegraph communication over a single line?
- Phantom circuits
- Simplex circuits
- Intercommunicating circuits
- Duplex circuits
Correct Answer: Simplex circuits
Correct Answer Explanation: Simplex circuits were a notable innovation in communication, allowing for simultaneous telephone and telegraph transmission over the same line. This was achieved using impedance coils and condensers, separating the signals and preventing interference.
In a large city, what percentage of total daily calls typically occurred during the busy hour?
- About one-quarter
- About one-third
- About one-eighth
- About one-half
Correct Answer: About one-eighth
Correct Answer Explanation: The busy hour, typically the peak period of telephone use, accounted for roughly one-eighth of the total daily calls in large cities. This concentrated traffic during this period posed significant challenges for telephone exchanges and highlighted the need for efficient switching mechanisms.
What is the typical trunking factor, representing the ratio of actual to theoretical out-trunking, often observed in telephone systems?
- 25%
- 50%
- 75%
- 100%
Correct Answer: 75%
Correct Answer Explanation: The trunking factor, a measure of the efficiency of trunk utilization, typically hovered around 75%, indicating that more local calls were handled within an office than initially predicted. This demonstrated that trunk resources could be efficiently allocated and shared, reducing the need for excessive trunk capacity.
What was the approximate average time of a local telephone conversation during this period?
- 30 seconds
- 60 seconds
- 100 seconds
- 150 seconds
Correct Answer: 100 seconds
Correct Answer Explanation: The average duration of a local telephone conversation in the early 20th century was around 100 seconds, providing insight into the typical length of calls and their impact on traffic flow in telephone exchanges.
What is the name of a hybrid system that combined features of manual and automatic systems, automating the switching process while retaining the role of an operator for call handling?
- The automanual system
- The Lorimer system
- The Strowger system
- The Sabin-Hampton system
Correct Answer: The automanual system
Correct Answer Explanation: The automanual system was a hybrid approach that combined elements of manual and automatic systems. The switching process was automated, while an operator remained present for call handling and other tasks, offering a transition phase between manual and fully automatic systems.
What type of device used in automatic systems reduced the need for first selectors by connecting a subscriber line to an available first selector trunk?
- The master switch
- The bridge cut-off relay
- The line switch
- The trunk repeater
Correct Answer: The line switch
Correct Answer Explanation: The line switch, a crucial component of automatic systems, optimized the use of selectors by directly connecting a subscriber line to an available first selector trunk. This ensured that calls were efficiently directed to the appropriate switching equipment based on traffic demand.
In automatic systems, what mechanism ensured that the next available trunk was ready for selection when a call was initiated?
- The line switch
- The bridge cut-off relay
- The trunk repeater
- The master switch
Correct Answer: The master switch
Correct Answer Explanation: The master switch in automatic systems played a vital role in maintaining trunk availability. It kept plungers pointing to idle trunks, ensuring that the next available trunk was ready for selection when a new call was initiated, preventing calls from being blocked due to busy trunks.
What type of relay, commonly found in common-battery multiple switchboards, disconnected the line relay from the line when a call was answered, simplifying jack design?
- The master switch
- The bridge cut-off relay
- The line switch
- The cut-off relay
Correct Answer: The cut-off relay
Correct Answer Explanation: The cut-off relay simplified the design of jacks in common-battery multiple switchboards by disconnecting the line relay from the line after a call was answered. This reduced the complexity of the jack mechanism and allowed for the use of smaller, more efficient jacks.
What specialized telephone system, limited to smaller installations, allowed for direct communication between stations without the need for an operator?
- Automatic systems
- Phantom circuits
- Private branch exchanges
- Intercommunicating systems
Correct Answer: Intercommunicating systems
Correct Answer Explanation: Intercommunicating systems were a type of telephone system designed for smaller installations, where each station was directly connected to every other station. This allowed subscribers to communicate directly without the need for a central switchboard or operator, providing a simpler and more efficient communication solution for smaller groups.
What is the name of the automatic system that used power-driven switches controlled by electrical impulses, providing an alternative to the widely used Strowger system?
- The Lorimer system
- The Strowger system
- The automanual system
- The Sabin-Hampton system
Correct Answer: The Lorimer system
Correct Answer Explanation: The Lorimer system, developed by the Lorimer brothers, was an alternative automatic system that utilized power-driven switches, controlled by electrical impulses, instead of the step-by-step mechanism used in the Strowger system. This mechanical approach offered a distinct alternative in automatic switching technologies.
What device, commonly used for charging batteries in telephone power plants, transformed alternating current into direct current?
- The iron-wire ballast
- The plug-seat switch
- The mercury-arc rectifier
- The Warner pole changer
Correct Answer: The mercury-arc rectifier
Correct Answer Explanation: The mercury-arc rectifier was a device used in telephone power plants to convert alternating current (AC) into direct current (DC). This was crucial for charging batteries, as telephone systems required a stable DC power supply for operation. The mercury-arc rectifier provided a reliable and efficient method for converting AC to DC.
What is the name of the large-scale transfer system that once served thousands of lines in San Francisco but was later replaced by multiple switchboards?
- The Strowger system
- The Lorimer system
- The automanual system
- The Sabin-Hampton system
Correct Answer: The Sabin-Hampton system
Correct Answer Explanation: The Sabin-Hampton system was a significant transfer system that served thousands of lines in San Francisco during a period of rapid growth. However, it was eventually replaced by more efficient and scalable multiple switchboards, reflecting the ongoing advancements in telephony technology.
What type of circuit, discussed in the Cyclopedia, allowed for more communication channels than the number of physical wire pairs by utilizing repeating coils and transpositions?
- Phantom circuits
- Simplex circuits
- Intercommunicating circuits
- Duplex circuits
Correct Answer: Phantom circuits
Correct Answer Explanation: Phantom circuits were a clever innovation that enabled the creation of additional telephone lines over existing wire pairs. By utilizing repeating coils and transpositions, phantom circuits effectively increased the capacity of existing cable runs, making communication more efficient and cost-effective.
What device, operated by the insertion or removal of a plug, could be used for switching or signaling purposes in telephone systems?
- The iron-wire ballast
- The plug-seat switch
- The mercury-arc rectifier
- The Warner pole changer
Correct Answer: The plug-seat switch
Correct Answer Explanation: The plug-seat switch was a simple yet versatile device used in telephone systems for switching and signaling. By inserting or removing a plug, operators could establish or break connections, or activate signals, allowing for flexible control and management of telephone circuits.
What is the name of an early attempt at increasing the capacity of multiple switchboards by dividing the multiple into sections, which was later abandoned in favor of smaller, more efficient boards?
- The Divided Multiple switchboard
- The Sabin-Hampton system
- The automanual system
- The Lorimer system
Correct Answer: The Divided Multiple switchboard
Correct Answer Explanation: The Divided Multiple switchboard was an early approach to expanding the capacity of multiple switchboards by dividing the multiple into sections. However, this design proved less efficient and was eventually abandoned in favor of smaller, more streamlined multiple switchboards, reflecting the ongoing optimization of telephone systems for greater efficiency and capacity.
What type of device, used in automatic systems, allowed for the automatic selection of an idle trunk from a group of lines, ensuring that a call was not missed due to busy lines?
- The master switch
- The bridge cut-off relay
- The line switch
- The rotary connector
Correct Answer: The rotary connector
Correct Answer Explanation: The rotary connector was a specialized device in automatic systems that facilitated efficient trunk selection. It automatically scanned a group of lines and selected an available trunk, preventing calls from being blocked due to busy lines. This ensured a smooth and reliable connection for callers.
What is the name of a feature in multiple switchboards that allows each operator to connect to any subscriber line in the exchange without the need for assistance from other operators?
- The busy test
- The line switch
- The multiple jack
- The cut-off relay
Correct Answer: The multiple jack
Correct Answer Explanation: The multiple jack was a key component in multiple switchboards, providing a connection point that allowed any operator to access a specific subscriber line. This feature eliminated the need for operators to rely on each other for connecting calls, allowing for greater flexibility and efficiency in handling telephone traffic.
What is the name of a specialized jack on a switchboard that allows the operator to answer an incoming call from a specific subscriber line?
- The busy test
- The line switch
- The multiple jack
- The answering jack
Correct Answer: The answering jack
Correct Answer Explanation: The answering jack was a dedicated jack on a switchboard that allowed the operator to directly answer an incoming call from a specific subscriber line. This streamlined the call handling process, enabling operators to quickly respond to calls and connect callers efficiently.
What is the name of a system that relies on a centralized battery at the central office to power subscribers’ instruments and operate signals?
- Automatic system
- Common-battery system
- Magneto system
- Strowger system
Correct Answer: Common-battery system
Correct Answer Explanation: Common-battery systems represented a significant advancement in telephone technology, centralizing power at the exchange and eliminating the need for individual batteries at subscriber stations. This centralized approach simplified maintenance, improved signaling, and contributed to overall efficiency.
In automatic systems, what device, one for each subscriber line, connected the line to an available first selector trunk, optimizing the use of selectors based on traffic demand?
- The master switch
- The bridge cut-off relay
- The line switch
- The trunk repeater
Correct Answer: The line switch
Correct Answer Explanation: The line switch was a crucial component in automatic systems, efficiently connecting subscriber lines to available first selector trunks. This optimized the use of selectors based on traffic demands, ensuring that calls were efficiently directed to the appropriate switching equipment.
What feature, usually in the form of lamps, alerted the operator when a subscriber hung up their receiver, indicating the need to disconnect the call?
- The pilot lamp
- The cut-off relay
- The busy test
- The supervisory signals
Correct Answer: The supervisory signals
Correct Answer Explanation: Supervisory signals, often implemented as lamps on switchboards, alerted operators to the status of calls. When a subscriber hung up their receiver, a supervisory signal would activate, indicating that the call was complete and needed to be disconnected. These signals were essential for efficient call management in manual switchboards.
What lamps, located on the switchboard, signal the operator that a call is waiting, allowing them to quickly locate the specific line?
- The supervisory signals
- The pilot lamps
- The cut-off relay
- The busy test
Correct Answer: The pilot lamps
Correct Answer Explanation: Pilot lamps, often arranged on a switchboard, acted as visual indicators for incoming calls. When a subscriber initiated a call, the corresponding pilot lamp would illuminate, alerting the operator to the waiting call and allowing them to quickly identify the specific line. These lamps were essential for efficient call handling in manual switchboards.
What is the name of a device in automatic systems that disconnected operating magnets after they had served their purpose, saving energy and improving efficiency?
- The master switch
- The bridge cut-off relay
- The line switch
- The trunk repeater
Correct Answer: The bridge cut-off relay
Correct Answer Explanation: The bridge cut-off relay was a device in automatic systems that ensured efficient power management. After an operating magnet had completed its function in the switching process, the bridge cut-off relay disconnected it, preventing the magnet from continuously drawing power. This saved energy and improved the overall efficiency of the automatic system.
What is the approximate capacity of a large storage battery cell, typically found in telephone exchanges?
- 100 ampere hours
- 1000 ampere hours
- 4000 ampere hours
- 10000 ampere hours
Correct Answer: 4000 ampere hours
Correct Answer Explanation: Large storage battery cells, crucial for providing backup power in telephone exchanges, typically had a capacity of around 4,000 ampere hours. This capacity ensured that the exchange could operate for an extended period, even in the event of a power outage, guaranteeing continued communication services.
What is the name of a type of circuit that eliminates the need for a ground connection at the subscriber’s station, simplifying the subscriber’s telephone and improving the reliability of the system?
- Duplex circuit
- Simplex circuit
- Phantom circuit
- Two-wire system
Correct Answer: Two-wire system
Correct Answer Explanation: The two-wire system was a significant improvement in telephone technology, eliminating the need for a ground connection at the subscriber’s station. This simplified the subscriber’s telephone and improved system reliability by reducing the potential for interference and ground faults.
What is the approximate number of conversations per busy hour that a single trunk in a manual system could handle?
- 2 to 4.6
- 7 to 15
- 15 to 34
- 100 to 200
Correct Answer: 7 to 15
Correct Answer Explanation: A single trunk in a manual system typically had a capacity of handling around 7 to 15 conversations per busy hour. This capacity was determined by factors such as the number of trunks in a group and the duration of conversations.
What is the approximate number of conversations per busy hour that a single trunk in an automatic system could handle?
- 2 to 4.6
- 7 to 15
- 15 to 34
- 100 to 200
Correct Answer: 15 to 34
Correct Answer Explanation: Automatic systems generally offered higher trunk efficiencies compared to manual systems. A single trunk in an automatic system could handle around 15 to 34 conversations per busy hour due to factors such as quicker answering times and shorter conversation durations.
What is the approximate number of conversations per busy hour that a single long-distance trunk could handle?
- 2 to 4.6
- 7 to 15
- 15 to 34
- 100 to 200
Correct Answer: 2 to 4.6
Correct Answer Explanation: Long-distance trunks, which connected different telephone exchanges over longer distances, typically had a lower capacity compared to local trunks. A single long-distance trunk could handle around 2 to 4.6 conversations per busy hour due to the increased signal attenuation and complexity of long-distance connections.
What is the approximate rate at which telephone train dispatching circuits could handle calls, reflecting the efficiency and speed of the selector system?
- 1 call per second
- 5 calls per second
- 10 calls per second
- 20 calls per second
Correct Answer: 10 calls per second
Correct Answer Explanation: Telephone train dispatching circuits were designed for rapid and reliable communication between train stations. These circuits utilized specialized selector systems that could handle calls at a rate of approximately 10 calls per second, ensuring fast and efficient communication for managing train operations.
In the automanual system, what was the average subscriber waiting time, highlighting the efficiency of this hybrid system?
- 0.5 seconds
- 1.07 seconds
- 2.07 seconds
- 5 seconds
Correct Answer: 2.07 seconds
Correct Answer Explanation: The automanual system, a hybrid approach combining manual and automatic elements, demonstrated impressive efficiency in handling calls. The average subscriber waiting time in this system was around 2.07 seconds, showcasing its ability to respond quickly to calls and provide efficient service.
What is the name of a specialized relay in automatic systems that connects a subscriber line to an available first selector trunk?
- The master switch
- The bridge cut-off relay
- The line switch
- The trunk repeater
Correct Answer: The line switch
Correct Answer Explanation: The line switch, a key component in automatic systems, connected subscriber lines to available first selector trunks. This optimized the use of selectors based on traffic demands, ensuring efficient routing of calls and preventing bottlenecks in the switching process.
What is the approximate number of calls per hour per operator that automatic systems could handle, demonstrating the efficiency of automated switching?
- 100
- 500
- 1000
- 5000
Correct Answer: 1000
Correct Answer Explanation: Automatic systems, with their automated switching mechanisms, significantly improved call handling efficiency compared to manual systems. They could handle traffic from around 1,000 calls per hour per operator, highlighting the significant increase in call handling capacity compared to manual systems.