US Army Signal Corps.
Now the heraldry makes sense. The red square is from a semaphore flag.
FWIW... here's a neat Google trick for things like this...
Go to images.google.com (Google Images)... click on the little camera.
You can upload a picture, or paste a URL for any image.
Google will find all matches, or similar images... and display the results. In this case, it found that the image was associated with "us army signal corps".