A total of four pulse phaser cannon assemblies are located in forward-facing locations onboard Defiant-class vessels. The cannons are located above and below the nacelle root attachments on the main body on both port and starboard sides of the ship. Due to the ship’s extreme maneuverability, yard engineers deemed it unnecessary to mount aft-facing cannons onboard vessels of this class. Computer simulations also indicated an unacceptable loss in phaser power performance due to increased strains on the power systems from the proposed aft-mounted cannons.

The development of the pulse phaser cannon applies a number of lessons learned at the Starfleet Tokyo R&D facility, where large, nearly flawless emitter crystals had been grown in ground-based microgravity chambers. The new crystals, combined with rapid-discharge EPS capaciter banks and high-speed beam-focusing coils, allowed the phaser discharge to be stored temporarily (up to 2.1 nanoseconds) within the coils and then released as a layered pulse structured something like an onion and is able to land a target contact that is more difficult to disperse than a standard phaser beam. Four pulse phasers are located above and below the nacelle root attachments on the main body.

Because pulse phaser cannons store up their charge between 1.7 and 2.1 nanoseconds the resulting energy pulse is more powerful then standard Type-X phaser emitters. Rapid fire of multiple bursts is accomplished through a direct EPS shunt from the warp reactor. If situations warrant, power can be routed from the impulse engines through a secondary plasma tap. For maximum effectiveness, all four cannons fire several bursts at the same time, resulting in a large amount of energy impacting a relatively small location. This tactic has been proven to pierce the shields of threat vessels without having to collapse the entire grid. Maximum energy output of a pulse phaser cannon is 300,000 terawatts.