ERCES / BDA Practice Questions

1. 80%
2. 90%
3. 95%
4. 99%

Answer: C. IFC Section 510 requires 95% of all areas on each floor to meet the signal strength criteria, and 99% in designated critical areas. NFPA 1221 and 1225 have used a different general-area percentage, so check which document the jurisdiction adopts; the 99% figure for critical areas is common to both.

Topic: Coverage requirements

1. Open office floors
2. Parking garage drive aisles
3. Tenant storage rooms
4. Exit stairways

Answer: D. Critical areas under IFC 510 and NFPA 1225 include the fire command center, the fire pump room, exit stairs and exit passageways, elevator lobbies, standpipe cabinets, sprinkler sectional valve locations and any other area designated by the fire code official. Open office floors are general areas held to the lower percentage.

Topic: Coverage requirements

1. Yes, because −98 is a larger number than −95
2. No, −98 dBm is 3 dB weaker than the minimum
3. Yes, as long as the audio quality is acceptable
4. No, because readings must be positive dBm values

Answer: B. Negative dBm values become more negative as the signal gets weaker, so −98 dBm is 3 dB, or half the power, below the −95 dBm minimum and the grid fails. Delivered audio quality (DAQ) is a separate criterion and does not override a signal strength failure.

Topic: Coverage requirements

1. Linking the building system to the outside public safety radio site
2. Radiating signal into stairwells and other critical areas
3. Supplying DC power to the remote DAS units
4. Combining the uplink and downlink onto one coaxial cable

Answer: A. The donor antenna, usually a directional antenna on the roof aimed at the public safety radio site, is the system's link to the outside network. Indoor coverage comes from the distributed antenna system (DAS) of coaxial cable or fiber, splitters and indoor antennas on the other side of the signal booster.

Topic: System components

1. Amplifies both the inbound and the outbound radio signals
2. Converts the radio signal to light for the fiber backbone
3. Boosts only the signal from the donor site into the building
4. Switches between two donor sites for redundancy

Answer: A. A bi-directional amplifier amplifies the downlink from the donor site into the building and the uplink from portable radios back out, so responders can both hear and be heard. A device that boosted only the inbound path would leave portable radios inside the building unable to reach the dispatcher.

Topic: System components

1. NEMA 1
2. NEMA 3R
3. NEMA 4
4. NEMA 12

Answer: C. Both documents require the signal booster and its associated active components to be housed in a NEMA 4 type waterproof enclosure. NEMA 1 and NEMA 12 are indoor ratings that provide no protection against water, and NEMA 3R is a rain-resistant outdoor rating that falls short of NEMA 4.

Topic: Power and monitoring

1. 15 Ah
2. 30 Ah
3. 45 Ah
4. 60 Ah

Answer: D. Capacity equals current multiplied by time: 2.5 A × 24 h = 60 Ah, which is then increased by any derating factor and rounded up to a standard battery size. The 30 Ah answer would cover only 12 hours, so always confirm the standby period the adopted code and the AHJ require.

Topic: Power and monitoring

1. Failure of the battery charger
2. Ambient temperature in the equipment room
3. Measured signal strength on each floor
4. Insertion loss of the coaxial cable runs

Answer: A. IFC 510 and NFPA 1225 require annunciation of loss of normal AC power, failure of the battery charger, low battery capacity, antenna malfunction and signal booster failure. Floor-by-floor signal strength and cable loss are verified during acceptance and annual testing, not monitored continuously.

Topic: Power and monitoring

1. −148 dBm
2. −18 dBm
3. −2 dBm
4. +18 dBm

Answer: B. Work the link budget in decibels: −75 dBm + 65 dB of gain − 8 dB of loss = −18 dBm. Gains add to and losses subtract from a dBm level, and multiplying or dividing the values is the classic mistake; for reference, 0 dBm is 1 milliwatt and 30 dBm is 1 watt.

Topic: RF basics

1. To keep amplified output from feeding back and oscillating
2. To keep the uplink and downlink channels from mixing
3. To protect the booster from lightning on the donor cable
4. To reduce the DC current the booster draws from its batteries

Answer: A. If the signal radiated by one set of antennas reaches the booster's input at a level greater than the loss between them, the amplified output feeds back on itself and the booster oscillates, jamming the public safety channels. That is why isolation must exceed the gain by a margin and why signal boosters include oscillation detection.

Topic: RF basics

1. 10
2. 12
3. 20
4. 40

Answer: C. Both documents divide each floor into 20 approximately equal test areas, with the portable radio tested in the center of each grid and the results compared with the required general-area and critical-area percentages. A 10-grid test would be too coarse to demonstrate 95% coverage.

Topic: Testing

1. Monthly
2. Quarterly
3. Semiannually
4. Annually

Answer: D. IFC 510 and NFPA 1225 require the system to be inspected and tested at least annually, including the signal booster and other active components, the batteries under load, and the monitoring connections to the fire alarm system. The jurisdiction may call for a repeat of the full coverage grid test at a set interval.

Topic: Testing

1. Any state-licensed fire alarm technician
2. A NICET Level III fire alarm technician
3. A person holding an FCC General Radiotelephone Operator License
4. The building's licensed electrical contractor

Answer: C. IFC 510 requires all tests to be conducted, documented and signed by a person holding a current FCC General Radiotelephone Operator License (GROL), together with certification of training from the equipment manufacturer. NICET certification is valuable, but it is not the credential the IFC names for signing the test.

Topic: Testing

1. The building owner, by obtaining a new FCC license
2. The county agency that holds the license for those frequencies
3. The signal booster manufacturer
4. The fire alarm monitoring company

Answer: B. FCC Part 90 allows a signal booster to be operated only by the licensee of the frequencies it retransmits or with that licensee's express consent, so the county public safety agency must authorize it. The building owner does not obtain a separate license for the booster, and the manufacturer's Part 90 equipment certification is a different requirement.

Topic: FCC rules

1. Class A amplifies only the uplink; Class B amplifies both
2. Class A is for indoor use; Class B for outdoor use
3. Class A is battery powered; Class B is AC powered
4. Class A is narrowband (75 kHz or less); Class B broadband

Answer: D. Part 90 defines a Class A (narrowband) booster as one with a passband of 75 kHz or less that retransmits one or a few channels, and a Class B (broadband) booster as one with a passband wider than 75 kHz. Class B boosters must also be registered with the FCC before they are operated.

Topic: FCC rules