Most of the Book Signal Corps in the Army Linage Series, with Heraldic Items for Signal Units (Commands, Brigades and Battalions) can be found on Google Books:

http://books.google.se/books?id=HrjJ_l1cz10C&printsec=frontcover&dq=signal+corps&hl=sv&sa=X&ei=JHplUdGbKMXa4ASA8oH4AQ&redir_esc=y#v=onepage&q=signal corps&f=false

Nice find. Thanks for the share.

You are welcome Snyder