"First Sergeant's Call" is a

bugle call A bugle call is a short tune, originating as a military signal announcing scheduled and certain non-scheduled events on a military installation, battlefield, or ship. Historically, bugles, drums, and other loud musical instruments were used ...

which signals that the

First Sergeant First sergeant is typically a senior non-commissioned officer rank, used in many countries. Singapore First sergeant is a Specialist (Singapore), specialist in the Singapore Armed Forces. First sergeants are the most senior of the junior spe ...

is about to form the company. \header \paper \score

References

bands.army.mil
{{music-instrument-stub Bugle calls