24-Hour Clock & Phonetic Alphabet

The 24-Hour Clock

Security operations run around the clock, and notebook entries, incident reports, and radio transmissions must record time without ambiguity. The 24-hour clock (sometimes called "military time") solves a problem the 12-hour AM/PM system creates: the same numbered hour appears twice a day, so "3:00" could mean 3 AM or 3 PM unless a label is added. In a legal record, that ambiguity is unacceptable.

How It Works

The 24-hour day runs from 0000 (midnight) to 2359 (one minute before the next midnight). There is no AM or PM.

The official Alberta Basic Security Training Participant Manual writes 24-hour times as four digits with no colon — it converts "1:30 PM" to 1330, and its model incident reports show entries such as "Time: 1116". Use that four-digit form in your notebook, in your reports, and on the exam. (A colon-separated form such as 13:30 is common in other industries and is equally unambiguous, but the four-digit form is what the Alberta course material teaches and tests.)

• 0000 = midnight (start of the day)
• 1200 = noon
• 1300 = 1:00 PM
• 2300 = 11:00 PM
• 2359 = one minute before midnight

Conversion Rules

Conversion shortcut:

• For AM times from 1:00 to 11:59, the hour is the same (just drop "AM" and add a leading zero; 12 AM becomes 00).
• For PM times from 1:00 to 11:59, add 12 to the hour. (1 PM + 12 = 1300; 11 PM + 12 = 2300.)
• 12:00 PM (noon) stays 1200.
• 12:00 AM (midnight) becomes 0000.

In a notebook, write the time as four digits with no colon and no AM/PM: 1430, not "2:30 PM". Always include the leading zero — 0715, never "715".

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The Phonetic Alphabet

When a guard radios in a licence plate, a suspect's name, or a building address, audio is rarely perfect. Radio static, background noise, and similar-sounding letters (think B and P, M and N, S and F) make it easy for the listener to write down the wrong letter. The NATO phonetic alphabet solves this by giving every letter a distinctive, agreed-upon word.

Security workers in Alberta are expected to know and use this alphabet for any spelling-out task over radio or phone.

The Full NATO Phonetic Alphabet

How to Use It

To spell a licence plate like ABC-123 over the radio, you would say: "Alpha, Bravo, Charlie, one, two, three." (The Alberta manual prints the words in the international spellings — note Juliett with two Ts and X-ray with a hyphen.)

To spell a surname like Ng, you would say: "November, Golf."

Key usage rules:

• Speak each word clearly and at an even pace. Do not rush.
• Use the standard word, not a made-up substitute. "Apple" is not the same as "Alpha." Standardization is the whole point.
• Numbers are spoken individually — "one, two, three," not "one hundred twenty-three."
• If the receiver did not catch it, repeat the entire sequence, not just the last letter.

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Why Both Tools Matter Together

A notebook entry that reads "Incident at 1430, suspect vehicle plate Alpha-Bravo-Charlie one-two-three" is unambiguous and verifiable. The same entry written as "Incident at 2:30, plate ABC 123" leaves room for doubt: 2:30 AM or PM? Was that "B" or "P" on the radio? In a legal proceeding, that doubt can cost the case. The 24-hour clock and the phonetic alphabet are not formalities — they are the tools that make a guard's observations stand up in court.

Common 24-Hour Clock Errors Candidates Make

Most ABST candidates lose marks not on the conversion rule but on its edge cases:

• 12:00 AM becomes 0000, not 2400. Midnight is the start of the new day, written 0000; "2400" appears in timetables but is not a valid notebook time.
• 12:00 PM stays 1200. Noon does not get 12 added — the 12 PM hour is the one hour that does not change.
• The midnight rollover. An event from 2355 to 0010 spans two dates. Record both: start 2355 on 4AUG2026, end 0010 on 5AUG2026.
• Adding 12 to AM hours. A PM-only rule. 9 AM is 0900, not 2100.
• Minutes do not change. 9:30 PM becomes 2130; only the hour shifts.
• Leading zero. Times before 1000 need it: 0715, not 715.

Quick Answer: Only the 12 PM hour stays the same; 12 AM becomes 0000; for every other PM hour add 12 to the hour only. Minutes never change, and the entry is written as four digits with no colon.

Radio Procedure and the Phonetic Alphabet in Practice

On the radio, the phonetic alphabet is part of a disciplined routine. A standard call follows a set pattern: pause and listen before transmitting, address the recipient by callsign, convey your message, and end with your callsign and "over." Before spelling anything, say "I spell" so the receiver is ready: "Suspect surname, I spell: November, Golf."

If the receiver misses a word, the correct response is "Say again," not "repeat" — "repeat" can be misheard as an instruction to do something again. Numbers are spoken individually: "one, two, three," not "one hundred twenty-three."

Exam Traps on Time and Phonetics

• A question lists "12:00 AM" as an incident time; the correct 24-hour entry is 0000, not 2400.
• A question gives "7:45 PM" and offers 1945 and 0745; the PM conversion (add 12) gives 1945.
• A question asks for the word for "P" and includes "Papa" alongside "Peter" or "Poppa" — only Papa is standard NATO.
• A question uses non-standard words ("Apple" for A) — the answer is Alpha, always.