SST (Pakistan Educators Recruitment Tests) flashcards
SST · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Ohm's law
- Voltage equals current multiplied by resistance (V = I × R); power equals voltage times current (P = V × I). Used to size wire and verify circuit loads.
- Supervised alarm zone
- A detection circuit continuously monitored by the panel for opens and shorts, typically through an end-of-line resistor, so a wiring fault annunciates as a trouble condition.
- Normally closed intrusion loop
- Devices wired in series so the loop carries current in the normal state; the panel signals an alarm when a device opens the circuit.
- Fail-safe lock
- Door hardware that is locked while energized and releases automatically when power is removed, permitting egress during a fire alarm or power failure.
- End-of-line resistor
- A resistor at the far end of a supervised zone that produces the reference current the panel expects; its value must match the programmed zone type.
- Class 2 circuit
- A power-limited circuit under NEC Article 725 whose energy is limited so it presents reduced fire and shock hazard; typical for alarm and signaling wiring.
- Cat6 channel length limit
- A horizontal cable channel, including all patch and equipment cords, may not exceed 100 meters (328 feet); the permanent link is limited to 90 meters.
- RS-485 bus limits
- Up to roughly 1200 meters (4000 feet) of twisted pair in a daisy chain, with 120-ohm termination at both physical ends and no star branches.
- T568B pin order
- Pins 1 through 8 are white-orange, orange, white-green, blue, white-blue, green, white-brown, brown; used for RJ45 plugs, jacks and patch panels.
- PoE 802.3at budget
- Power over Ethernet Plus delivers 30 watts at the power sourcing equipment and guarantees 25.5 watts at the powered device over two pairs.
- Standby battery sizing
- Amp-hour capacity equals standby current times standby hours plus alarm current times alarm hours, multiplied by a 1.25 derating factor for aging.
- Plenum-rated cable
- Cable listed CMP, required in air-handling spaces because of its low smoke and flame-spread characteristics; unlisted substitutes are not permitted in plenums.
- Sealed lead-acid service life
- Standby batteries typically last three to five years; a load-test capacity below 80 percent of the rated amp-hour value indicates replacement is due.
- Video storage estimate
- One camera recording at 1 Mbps produces about 10.8 gigabytes per day; multiply by camera count and retention days for total storage.
- Cross-zoning
- An alarm verification method requiring two detectors in the same area to trip within a defined time window before the panel transmits an alarm.
- NTP time synchronization
- Network time protocol keeps panels, recorders and servers on a common clock so events in different logs can be correlated during an investigation.
- Daily test signal
- A scheduled automatic transmission from the protected premises to the monitoring center; its absence is treated and reported as a communication trouble.
- Resistance measurement rule
- Resistance is measured only with power removed and the component isolated from parallel paths; otherwise the meter reading is invalid.
- Half-split fault isolation
- Dividing a circuit at its midpoint, testing each half, and repeating on the faulty half locates a fault in a logarithmic number of tests.
- Time domain reflectometer
- A test instrument that sends a pulse down a cable and measures reflection delay to report the distance to an open, short or impedance mismatch.
- Ground fault on a loop
- Unintended leakage to earth, detected by measuring resistance from each conductor to ground; the low reading identifies the faulted leg.
- Ping test
- An ICMP echo request sent to an IP device that confirms network reachability and round-trip time, separating addressing faults from hardware faults.
- NFPA 72 scope
- The national code covering selection, installation, testing, inspection and maintenance of fire detection and alarm systems and emergency communications systems.
- NFPA 731 scope
- The installation standard for premises security systems, covering intrusion detection, access control and surveillance design, installation, testing and maintenance.
- NEC Article 760
- The article governing fire alarm system wiring and cable types such as FPL, FPLR and NPLF, including installation methods and marking requirements.
- Lockout tagout
- The OSHA 1910.147 requirement to isolate, lock and tag all hazardous energy sources before servicing equipment, verified by an attempted start.
- Fall protection trigger
- General industry requires fall protection at four feet above a lower level; construction work requires it at six feet above a lower level.
- Firestopping
- A listed material and system used to seal penetrations of rated walls and floors so the assembly's fire resistance rating is restored.
- Record of Completion
- The NFPA 72 document listing installed devices, system features and test results, signed by the installing contractor and the owner's representative.
- As-built drawings
- Drawings revised during installation to show actual device locations, addresses, cable routes and panel positions as they exist in the field.
- Punch list
- A written record of outstanding deficiencies and incomplete work, with an assigned owner and due date, closed by signature before project acceptance.
- Handoff training record
- Documentation of the customer training session including date, topics covered, attendee names and signatures, serving as proof of knowledge transfer.