Phaser cannon

A phaser cannon was a type of directed energy cannon weapon, a powerful phaser bank, used by at least the, the Terran Rebellion and Species 6339. It has been utilized as a ground vehicle mounted turret gun and an embedded starship-mounted weapon system. 

Ship-mounted phaser cannon
The ship-mounted Federation cannon is an optronically targeted phaser. It was presumably first introduced in the starship. In the mirror universe, the Defiant phaser cannons were called multi-targeting phaser banks by the Klingons. 

The four cannons of the Defiant-class were usually seen firing phaser bolts simultaneously in short rapid-fire bursts and in only one direction. The cannons could also fire beams. The combined firepower of the four phaser cannons of the Defiant appears to have been almost as powerful as the combined firepower of two wing-mounted disruptor cannons on a Klingon Bird-of-Prey. 

Although the impostors displayed phaser cannons as the weapon systems of USS Voyager, there is no evidence that they were part of the actual armaments of the Voyager. 

Systems
On the Defiant-class the plasma conduit was run through the primary phaser coupling to almost double the power of the phaser cannons. On most Federation ships this would have significantly reduced the warp drive efficiency. Phaser safeties were engaged before the weapons array was brought on-line and the phaser cannons charged to full power. When the cannons were charged, fifteen-percent plasma was bled to the phaser matrix. There was also a separate phaser generator from the emitters. There were also phaser reserves that could be emptied, for example to strengthen structural integrity. There was a thirty-inch long power cell in the phaser array on the Defiant-class starships that was easily used up and needed to be replaced. 

With extensive modifications, involving shunting the primary phaser relay through the warp drive, and bypassing the plasma emitter from the emitter coupling servos to avert an overload, phaser cannon array could be modified to emit a phaser beam wide enough to encompass an entire comet and vaporize it evenly from a distance of ten kilometers. 

In 2373 the throughput reading of the phaser relay on the Defiant was 148.7. Lieutenant Commander Worf and Ensign Nog attempted to increase the relay efficiency. This process involved recalibrating the emitter stage after the interface program was initialized and prefire chamber charged. 

Other species phaser cannons
Species 6339 utilized phaser cannon technology. One of their vessels, commanded by Ven, encountered by the USS Voyager in 2375, was found to possess 22 phaser cannons on the aft section alone. 

Ground vehicle-mounted phaser cannon
Ground vehicles could be equipped with a personnel-operated phaser cannon. The Argo shuttlecraft, attached to the USS Enterprise (NCC-1701-E), was equipped with a buggy which was armed with such a device. 

Background
It is a common interpretation that the Federation phaser cannon was also developed specifically against Borg ships, as the Defiant-class was designed only for the one purpose, to fight and defeat the Borg and it was presumably the first shiptype to use a phaser cannon. 

The script of named the weapon a  phaser. There is however no evidence of any rotating barrels. On-screen, in the dialogue, the Defiant cannons were called simply phaser banks (, etc.) or just the phaser array. The four cannon simultaneous phaser volley of fifteen shots (sixty bolts total) was called "a standard burst" in "Destiny". Star Trek: Starship Spotter identifies the classification of the cannons as Type XII phasers.

In the first draft of the script of  the USS Enterprise (NCC-1701-E) was also intended to have port and starboard batteries of rapid-fire phasers resembling Gatling guns in their effect. They were able to destroy a Borg cube before the Borg ships adapted their shields to the cannons.

In the Star Trek: Deep Space Nine Technical Manual, the Defiant's phaser cannons are called "pulse phasers" or "pulse phaser cannons." The weapon combines several new technologies, such as nearly flawless emitter crystals, rapid discharge EPS capacitance banks and high-speed beam-focusing coils. The pulses are structured like a layered onion. As a result, the target contact is more difficult to disperse than a standard phaser beam. On the Defiant, the EPS weapon-power conduits have been truncated to provide a near zero lagtime between activation command and beam launch. (pg. 123, 132, 133) starships were also armed with two pulse phaser cannons. (pg. 154)

In the script of, when Captain is recruiting  to join Starfleet, he comments on the cadets who fought with Kirk in the Shipyard Bar, that "they'll run home to momma the minute they're looking down the barrel of a Klingon phaser cannon." This suggests Klingons were using phaser cannons during the mid-23rd century of the alternate reality. 

Apocrypha
According to the Pocket Books novelization The Search, by Diane Carey, the phaser cannon is called a triple-redundant interlocking phaser array. According to the novel A Sea of Troubles, the Miranda-class starship was upgraded with Defiant-class type pulse phasers. According to the novel Gods of Night, the starships were armed with Mark XII phaser cannons.

The, a prototype starship featured in the Ships of the Line 2009 calendar, also features rapid fire pulse phasers in its arsenal, according to its designer Mark Rademaker. 

The video game manual for Star Trek: Starfleet Command III describes the phaser cannon in great detail:


 * "The Pulse Phaser is an advanced heavy weapon designed for a high rate of fire and a high damage yield ... The Pulse Phaser was developed by Starfleet as a weapon to combat future Borg incursions and was first fitted onto the prototype U.S.S. Defiant. The device functions similarly to a standard Phaser, but without a continuous beam. The energy emissions are instead stored in a magnetic field, allowing them to coalesce and agitate to higher energy states. The field is then redirected, forcing the burst of Phaser energy toward the target. This process is repeated rapidly using multiple magnetic field generators, and the result is a stream of phased energy projectiles. Although the range of such a weapon is much less than the standard Phaser due to rapid dissipation, from close range the pulse Phaser can do more damage than most Phaser types. The weapon has since been adapted to function on most Federation ships."

The video game Star Trek: Armada II also describes the phaser cannon as a pulse phaser on board Defiant-class ships, the Defiant-class variant ships,  ships, Federation starbases, and pulse phaser turrets. The Klingon scoutships were also armed with this weapon.

According to the video game Star Trek: Elite Force II, the USS Enterprise-E was also armed with a backup auxiliary twin pulse phaser cannon that was embedded into the primary hull. The cannon turret was capable of being manually operated by personnel in EVA suits.

Pulsphaser