Voice Communication Rules

Voice is the first choice of telecommunication mode when real-time information exchange is required. The inter-action between man and machine, between the user and the equipment, is straightforward and equipment other than the actual "radio" is not needed. Nevertheless, some basic rules need to be followed: initial emergency information transmitted in a voice message must be clear and concise. An initial emergency call should always contain information on

Supplementary information on specific needs, the best way to reach the location where assistance is needed, or on hazards potentially endangering the providers of assistance can be added to this basic information.

Depending on the quality of a voice link, it might be necessary to spell names of persons or places. Using a common spelling alphabet greatly facilitates this. The most commonly used alphabet is, even in languages other than English, the one used in the aeronautical, maritime and many military services, listed below.

In whatever language being used on a network, numbers should always be spelled out digit-by digit.

Example:  In English

"18014" is "one – eight – zero – one – four", and not  "eighteenthousendfourteen".

A typical communication on a voice network might sound as follows:

"BASE, this is MOBILE ONE, OVER"

Station "BASE" is calling station "MOBILE ONE" and asking this station to reply.

To identify each station, call signs are being used. Blocks of official call signs are allocated to each country by the ITU. The national administrations then attribute a specific call sign to each licensed station. However, local networks, such as typically used in emergency situations, often use "tactical call signs", which allow immediate identification of the station or the speaker. In any case, an overall concept or at least list of call signs used has to be established in order to know "who is who".

Examples of tactical call signs: BASE (for an operations centre), MOBILE ONE, MOBILE TWO and so on for vehicles, names of for locations such as villages or towns for fixed stations, and names or nicknames for individuals, code-words for institutions, or combinations of all the above.

A station calling another station will always say the call sign of the station called first, and the own call sign afterwards: "BASE this is MOBILE 1". The operator will then say "OVER", inviting the other station, in this case BASE 1" to reply.

In "simplex" mode each station can at any given time only speak or listen, receive or transmit. The operator of MOBILE ONE therefore has to invite station BASE to reply. This is done with the word OVER.

The other station replies:

"MOBILE ONE, this is BASE. ROGER, OVER"

The word ROGER means, "I understood", "I hear you". It is derived from a no longer used spelling alphabet: the letter "R" is the abbreviation for "understood" or "ok" in the morse code used on telegraphy links.

Station MOBILE will now transmit its message:

"BASE, this is MOBILE ONE. I am arriving in Porttown  - I SPELL: PAPA OSCAR ROMEO TANGO TANGO OSCAR WHIKSKY NOVEMBER at one four three zero hours. OVER"

The message contains a place name, which the operator spells out, as there might be several places with similar sounding names. The time of arrival, 14:30 hrs, is spelled out in single numbers. The final OVER again invites the other side to reply.

"MOBILE ONE from (or "this is") BASE, ROGER and OUT"

Station BASE has confirmed that the message was received and that the connection is terminated. "and OUT" tells other stations of the network, that the frequency is now free, and that they can make their calls.

In the above example, we have learned some of the most common abbreviations or code words used in all voice networks. Some other such words are

AFFIRMATIVE, simply meaning "yes", but better to understand. Its opposite is NEGATIVE, "no".

When repeating a word, it is important to say so. A particularly important word of a message might be emphasized ("underlined") this way:

"MOBILE ONE, this is BASE. Do not, I REPEAT: not, proceed without further instructions".

If a message is not understood, a station would reply, saying

"BASE from MOBILE ONE, NEGATIVE COPY, please REPEAT. OVER"

The larger a network is, the more important is communications discipline. Keeping messages as short as possible and respecting the traffic rules are the keys to efficient communication. Larger networks usually have a "net control station". This station has the same role as the chairperson has in a meeting:  Participants wishing to speak, ask the chairperson for permission, and the latter will, if necessary, determine the order in which speakers will be invited to address the meeting. If two stations on a busy network need to hold a longer conversation between them, the net control station might instruct them to contact each other on a separate frequency or channel, and to report back once their communication is terminated.

In an emergency network, discipline and short, concise messages are of particular importance. In international operations, the language spoken should always be the one that is best understood by everyone. Only the actual content of a message from one station to another station might better be transmitted in a language these two partners understand, but the procedures must be understandable for all partners.

More detailed voice communication rules are available at www.reliefweb.int/telecoms/training/unhcrradio.html