FIXED - A light showing continuously and steadily.

F         

OCCULTING - A light in which the total duration of light in a period is longer than the total duration of darkness and the intervals of darkness (eclipses) are usually of equal duration.
Single - An occulting light in which an eclipse is regularly repeated.

Oc         

Group - An occulting light in which a group of eclipses, specified in number, is regularly repeated.

Oc (2)         

Composite group - A light simular to a group-occulting light except that the successive groups in a period have differenct numbers of eclipses.

Oc (2+1)         

ISOPHASE - A light in which all the durations of light and darkness are equal.

Iso         

FLASHING - A light in which the total duration of light in a period is shorter than the total duration of darkness and the appearances of light (flashes) are usually of equal duration.

Single - A flashing light in which a flash is regulaly repeated (at a rate of less than 50 flashes per minute).

Fl         

Group - A flashing light in which a group of flashes, specified in number, is regulaly repeated.

Fl (3)         

Composite group - A light similar to a group-flashing light except that successive groups in a period have different numbers of flashes.

Fl (3+1)         

QUICK - A light in which flashes are repeated at a rate of not less than 50 flashes per minute but less than 80 flashes per minute.

Continuous - A quick light in which a flash is regularly repeated.

Q         

Interrupted - A quick light in which the sequence of flashes is interrupted by regularly repeated eclipses of constant and long durations.

IQ         

MORSE CODE - A light in which appearances of light of two clearly different durations (dots & dashes) and grouped to represent a character or characters in the Morse Code.

Mo (Y)         

FIXED AND FLASHING - A light in which a fixed light is combined with a flashing light of higher luminous intensity.

FFl         

ALTERNATING - A light showing different colors alternately.

Al WR         
Al WG         
Al GR