WW2 Bugler's Function in Combat

I recently learned that my Uncle's MOS during the war was 803 Bugler. I know that he served in the European Theater in an infantry regiment's Headquarters Company.
I can understand what his function might have been while stationed stateside, but haven't determined what his day to day function might have been while the Regiment was involved in combat operations.

I haven't been above to find any information and would appreciate any help with this.

 

I'm not sure this will answer your question, but it is an interesting article about a WWII bugler.

National display shows local bugler during WWII days

 

Another article: http://www.24thida.com/stories/overcash_hoyts_war.html

 

Good find, Takao. From the article:

I never realized bugling would involve such hazardous duty. Delivering supplies to FOs was not a cake job.