Phonetic Alphabet and International Voice Procedures
06-03-2009 06:11
Operating a voice system depends largely on the skills of the involved persons. Proper voice procedure training should provide the operators with the basic knowledge of how to improve their skills in the use of radio communication. Even the best systems can suffer from interference and because of this is possible than the other part cannot hear (understand) the information passed. Therefore it is extremely important that proper voice procedure is used to save time. Briefly, a voice procedure is a set of rules designed to provide security, accuracy and discipline when speaking on the voice loop.

Phonetic alphabet

Letters, numbers and symbols

It is most important to use the accepted phonetic alphabet for letters and digits for all numbers, especially when voice transmissions are distorted, or when clear, accurate communication is essential.
Through world wide acceptance, certain acronyms may be given by letter only without using the phonetic alphabet. Examples of these are UT, GMT, JSC, PCM, UHF, VHF and SRB. Common usages of certain number sets allow the unambiguous use of word groupings rather than digits. Examples of these are "Three Seventy", "Seven Forty Seven" and "Building Thirty".
Note 1: "Fifty microvolt" can be misunderstood for "Fifteen microvolt", but "Five Zero microvolt" is unambiguous. "Test B" can be misunderstood for "Test D", but "Test Bravo" is unambiguous.
When transmitting times in Universal Time (UT), care must be exercised in the use of the letter "Z" since the phonetic pronunciations ("Zulu") could be mistaken for "Two Two". Additionally, sequences of numbers in time references are best identified as "days", "hours", "minutes" and "seconds" as applicable. The following examples illustrate the use of these techniques:
"Two seven six days, one two hours, three zero minutes, UT"
"One seven hours, three zero minutes, UT"

Basic aspects for international voice procedure

  • The official language to be used is English

It is most important to keep all voice traffic short, clear and concise, try to avoid lathering on with elaborate definitions and niceties which in the outcome only serve to disguise the requested information. This of course does not mean that conversation should be impolite, but it should be remembered that the operator is attempting to obtain information and not chatting about the weather.

  • Voice loop discipline should be maintained

Preserve VOICE LOOP DISCIPLINE; when many parties are sharing a Coordination loop, wait for a pause in traffic before issuing a call request. It is not only most annoying to be interrupted during an exchange by a third calling party; it can also lead to confusion of information. Should you need urgent contact to your opposing party then use the bellow defined "BREAK BREAK" interrupt, complete your exchange quickly and return the loop to the previous users.

In summary:
-listen before you speak
-think before you speak
-use correct voice procedure
-maintain constant radio watch
-answer calls promptly
-keep the lines free of unnecessary talk
-be brief and to the point
-use a voice technique which increases the performances of communication (keep adequate pauses, keep the conversation speed slower as normal conversation, speak directly into the microphone, the voice should be pitched at a higher level than for normal conversation)

Voice check procedure

As a common practice a party reports into a voice loop by a standard voice check.
When testing voice circuits, a standard short count (1, 2, 3, 4, 5,-5,-4,-3,-2,-1) should be spoken directly into the microphone at normal voice level. Voice checks provide the means to ensure that the circuit is operating, to check the intelligibility and quality of the speech on the circuit, and to verify that the speech is clearly understood and is of normal tonal quality for the type of circuit under test. The degree signal strength and readability of the transmission are expressed in the following terms or combinations; they may be stated by word or number:


Pro-words are used to indicate specific meaning that replaces abbreviated sentences or phrases.

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