This is a short bugle call played by military forces to wake up the soldiers at the start of the day. Alternatives to this call include Charlie Reveille, Long Reveille, Reveille (US) and The First Post. Well-known calls such as The Last Post and Taps mark the end of the day. See the links at the left to download the sheet music or audio files. More bugle calls are listed in our article about the history and cultural impact of Bugle Calls
The image below is the first page of the sheet music, and here you can download the full sheet music for Rouse (bugle call) in PDF format.