Wink pulsing

Wink pulsing: In telephone switching systems, recurring pulsing in which the off-condition is relatively short compared to the on-condition.

Note: On key-operated telephone instruments, the hold position, i.e., the hold condition, of a line is often indicated by wink pulsing the associated lamp at 120 pulses per minute. During 6% of the pulse period the lamp is off and 94% of the period the lamp is on, i.e., 30 ms (milliseconds) off and 470 ms on.

Source: from Federal Standard 1037C and from MIL-STD-188