VOLUME I Multinational Maritime Tactical Instructions and Procedures

MTP 1(D), Vol. I
Table 5-2. Radiation Status Indicators (RSIs)
The following RSIs indicate when equipment may be operated without seeking the OTC/CWC’s permission, or
operated outside the standard occasions for breaking silence:
A Aircraft May be operated if essential for safe operation of aircraft and helicopters.
B Night Between sunset and sunrise.
C Day Between sunset and sunrise.
D Distance When clear of nearest friendly unit or position designated. Distance to be
specified in miles (e.g., D30).
E Essential Transmission Essential transmissions maybe made without seeking the OTC/CWC’s permission.
(Note 1)
G Guard To be operated or guarded (COMMS) by unit designated on behalf of other
units. (Note 2)
S Silence No emissions permitted without the permission of the OTC/CWC or in accordance
with the standard occasions for breaking silence. Equipments that
“leaks” in dummy load or in standby should be switched off. (Note 3)
T Reduced Output Brilliance/output level reduced to the minimum level required for safety and/or
to obtain the required operational results.
U Transmitter Permitted Transmissions may be made. (Note 1)
X Specific Emissions The TCO/CWC must specify when the emitter may be used. (Note 4)
NOTES:
1. Units should transmit for as short a time as possible to achieve the aim, and should avoid emitters
that cause interference. Sonars may use random mode, scale, power, and frequency changes.
2. Details of guard ships and how they transmit information (e.g., data link) should be outlines in the
EP. The EMCON Plan must ensure that guard ships are provided with the means to transfer data to
the force. Guardship duties can be rotated at irregular intervals between appropriate units. RSI “G”
for communications should detail one unit for a named circuit (e.g., radar guard ship RSI “G” for HF
JAAWSC). This should not be confused with setting watch on circuits as detailed in the OPTASK
COMMS.
3. A blank space in any EMCON Plan is equivalent to the RSI “S” (silence).
4. XRAY is to be used to indicate unique occasions when an emitter may be used outside the standard
occasions for breaking silence and the occasions governed by the other RSIs. These may be,
for example, the deployment of decoys against radar satellites, the use of FC radars for height finding,
or the use of IFF systems. The OTC/CWC is to specify these occasions for each column.
5-11 ORIGINAL