R A N K     G U I D E S
Deep Space Nine (Enlisted and Warrant Officers)

Insignia	Starfleet Rank	Army Rank (Equivalent)
	Master Chief Petty Officer	Sergeant Major
	Senior Chief Petty Officer *	Senior Staff Sergeant
	Chief Petty Officer	Staff Sergeant
	Petty Officer, First Class	Sergeant
	Petty Officer, Second Class	Corporal
	Petty Officer, Third Class	Lance Corporal
- None -	Crewman	Private

Like the commissioned officers, the enlisted officers wear their ranks on the right-side of the collar, while their Combadges on the left-side of the uniforms.

Unfortunately there is not much information regarding the above insignia. The 3 editions of Star Trek Encyclopedia only covered the insignia for Commissioned Officers, but they are silent on Non-Commissioned Officers (NCOs).

According to Star Trek Magazine (May 2002 ed.), page 32, Chief Miles O'Brien is an enlisted officer who did not attend Starfleet Academy. Hence, he has to work himself up from rank and file, and has to salute to even the lowest ranking Commissioned Officer, such as Ensign Nog (Ferengi, nephew of Quark). Nevertheless, Starfleet Command does not discriminate between Officers and NCOs, but evaluate one's performance based on their own merits. Chief O'Brien was subsequently appointed as the Professor of Engineering at Starfleet Academy despite he's not a even graduate from the Academy.

*Chief Miles O'Brien worn the rank of Senior Chief Petty Officer on Deep Space Nine. It is therefore conjecture that the Starfleet ranks for Non-Commissioned Officers (NCOs) follows that of the U.S.Navy.