IMO Resolution A.422(XI) requires that certain indications and warnings be given on
an ARPA for anti-collision purposes. ARPA Video symbols 1 to 12, illustrated in
ANNEX 1, shall be used to conform with these IMO mandatory requirements.
Other symbols may be used for other anti-collision or navigational functions provided
they do not conflict with the symbols 1 to 12 in ANNEX 1. The use of these other
symbols shall be limited to ensure that they do not obscure the anti-collision
requirements of the ARPA.
For the three warning alarm symbols (Symbols 7,8 and 9) the following priorities
shall be used:
An unacknowledged warning alarm is always a higher priority than an
acknowledged warning alarm;
CPA/TCPA warning has a higher priority than a target entering guard zone
A Guard zone warning has a higher priority than a Lost target warning.
ARPA CONTROL NAMESE.4
The names indicated shall be used to describe ARPA controls.
If the ARPA has any of the 23 radar display controls of IMO Resolution
A.278(VIII), then those radar display names shall be used on the ARPA.
Abbreviations of names may be used.