In telecommunication, receiver attack-time delay is the time interval from (a) the instant a step rf signal, at a level equal to the receiver threshold of sensitivity, is applied to the receiver input to (b) the instant the receiver output amplitude reaches 90% of its steady-state value. Note: If a squelch circuit is operating, the receiver attack-time delay includes the time for the receiver to break squelch. Source: From Federal Standard 1037C and from MIL-STD-188