BREAK-IN PROCEDURES

A station having a message of higher precedence than the transmission in progress may break in and suspend that transmission in the following manner:

FLASH message-The station should break in at once and transmit the message.

IMMEDIATE message-The station may break in at once and pass the message. The station may make a preliminary call before transmitting the message, if necessary. On a directed net, the station must obtain control approval before transmitting the message.

PRIORITY message-The station should use the same procedure as for IMMEDIATE, except that only long ROUTINE messages should be interrupted.

You should be aware that the break-in procedure is not to be used during the transmission of a tactical message except to report an enemy contact. The precedence of the message spoken three times means to cease transmissions immediately. Silence must be maintained until the station breaking in has passed the message. In the following example, assume that Tecumseh is transmitting a message to Kamehameha on a free net and Key has a FLASH message for Polk. Key breaks in with the following transmission:

"FLASH, FLASH, FLASH, POLK, THIS IS Key, FLASH, OVER."

Polk replies:

"THIS IS Polk, ROGER, OVER."

Key then proceeds with the FLASH traffic and obtains a proper ROGER, thus freeing the net for further transmissions. After hearing "ROGER," Kamehameha recontacts Tecumseh for the remainder of the traffic that was being sent before the break-in:

"Tecumseh, THIS IS Kamehameha, ALL AFTER . . . . "

On a directed net, the station wishing to break in would first obtain permission from net control. For example, referring to figure 2-1, assume that Vallejo is transmitting a message to Kamehameha and Polk has FLASH traffic for Tecumseh. Polk notifies Key (net control):

"FLASH, FLASH, FLASH, Key, THIS IS Polk." FLASH For Tecumseh, OVER."

Key then answers:

"Polk, THIS IS Key, Send Your FLASH, OVER."

Upon hearing the authorization, Tecumseh transmits:

"THIS IS Tecumseh, OVER."

Polk proceeds:

"Tecumseh, THIS IS Polk, FLASH (sends message), OVER."

The preceding transmission would conclude after Polk had received a proper ROGER for the FLASH traffic. The two stations that were broken (Vallejo and Kamehameha) would reestablish communications using proper R/T procedures.

EMERGENCY SILENCE

Emergency silence may be imposed on an R/T net only by competent authority. If an authentication system is in effect, a station must always authenticate a transmission that:

Imposes emergency silence;

Lifts emergency silence; and

Calls stations during periods of emergency silence. When emergency silence is imposed, no receipt or answer for such transmissions is required.

To impose emergency silence, the NECOS speaks the proword SILENCE three times. For example, refer to figure 2-1 and assume that Key (net control) was authorized to impose emergency silence. Key would transmit:

"Poseidon, THIS IS Key, SILENCE, SILENCE, SILENCE, TIME One Four Four Zero Zulu, OUT."

To impose emergency silence on a particular frequency but not on all frequencies used in the net, Key would use the proword SILENCE (spoken three times), followed by a frequency or the frequency designator to be silenced. SILENCE (spoken three times), followed by the words "all nets,"means to cease transmissions immediately on all nets. All transmissions end with the proword OUT.

To lift emergency silence, Key would send the following transmission:

"Poseidon, THIS IS Key, SILENCE LIFTED, TIME One Five One Zero Zulu, OUT."