CED Radio & Telecommunication Systems 2 — Questions and Answers
Question 1: When a dispatcher receives a garbled transmission on the primary channel, what is the FIRST action they should take?
- Switch all traffic to the backup channel immediately
- Ask the unit to repeat the transmission and identify their location (Correct answer)
- Ignore the transmission and wait for the unit to call again
- Contact a supervisor before responding
Correct answer: Ask the unit to repeat the transmission and identify their location
The dispatcher should request a repeat and confirm unit identity to gather the information needed before taking further action.
Question 2: What does the term 'trunked radio system' refer to in public safety communications?
- A system that uses a single dedicated frequency for all traffic
- A system that dynamically assigns frequencies from a pool to users on demand (Correct answer)
- A legacy analog radio network with manual channel selection
- A system exclusively for inter-agency communications
Correct answer: A system that dynamically assigns frequencies from a pool to users on demand
A trunked radio system automatically assigns available frequencies from a shared pool, increasing efficiency and reducing channel congestion.
Question 3: Which radio transmission mode allows both parties to speak and listen simultaneously?
- Simplex
- Half-duplex
- Full-duplex (Correct answer)
- Multiplex
Correct answer: Full-duplex
Full-duplex allows simultaneous two-way communication, similar to a telephone call, because separate frequencies are used for sending and receiving.
Question 4: A dispatcher notices that a unit's radio transmission cuts off before the message is complete. This is MOST likely caused by:
- The unit releasing the PTT button too early (Correct answer)
- Interference from a neighboring jurisdiction
- A malfunctioning dispatch console
- Excessive traffic on the backup channel
Correct answer: The unit releasing the PTT button too early
Releasing the Push-To-Talk button prematurely is the most common cause of truncated transmissions in the field.
Question 5: What is the purpose of a 'talk group' in a digital radio system?
- To assign a unique ID to each individual radio
- To logically group users so they communicate on a shared virtual channel (Correct answer)
- To encrypt transmissions between dispatch and field units
- To boost signal strength in low-coverage areas
Correct answer: To logically group users so they communicate on a shared virtual channel
A talk group organizes users with shared operational needs onto a virtual channel within a trunked or digital network.
Question 6: In emergency communications, what does 'interoperability' specifically mean?
- The ability of different agencies' radio systems to communicate with each other (Correct answer)
- A dispatcher's ability to manage multiple incidents simultaneously
- The redundancy built into a CAD system
- The geographic range covered by a single repeater
Correct answer: The ability of different agencies' radio systems to communicate with each other
Interoperability is the capability for radio systems from different agencies or jurisdictions to exchange voice and data communications during incidents.
Question 7: Which piece of equipment is used to extend the range of portable radios in the field by receiving and retransmitting signals?
- Patch panel
- Base station
- Repeater (Correct answer)
- Simulcast transmitter
Correct answer: Repeater
A repeater receives a radio signal on one frequency and simultaneously retransmits it at higher power on another frequency to extend coverage.
CED Radio & Telecommunication Systems 2
When a dispatcher receives a garbled transmission on the primary channel, what is the FIRST action they should take?