When were the first combat troops sent to vietnam?

The term "combat troops" is confusing to civilians (and some military personnel too) because the term has been abused for so long. All US Army personnel are combat troops with specialized branches that specialize into specific combat jobs, formerly (which is why they used to go to BOOT CAMP; formerly known as Basic Combat Infantryman's Training) known as the combat arms branch: Armor (tanks), Artillery (cannons), and the Infantry (formerly fighting men/foot soldiers). During the late 1990 the US Army "may" have added other branches to that specialized combat arms system. Rumor control stated that the aviation branch was added to the combat arms system.

The combat arms of the US Army are the conventional fighting branches of the US Army (or was during the Viet War days).

US Combat troops, along with specialized troops were deployed to South Vietnam in 1955. CONVENTIONAL forces (those combat arms men previously discussed above were deployed in 1965).