Insignia Description
A Gold color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a shield blazoned as follows: Per bend Argent and Tenné in sinister chief a lamp of knowledge Sable, flamant Proper; and attached below the shield a Gold scroll inscribed “FIDELITER SERVIMUS” in Black letters.

Symbolism
The shield is in the colors of the Signal Corps. The lamp of knowledge represents scholastic activities of the school which the unit serves. The motto is translated “Faithfully We Serve.”

History
The distinctive unit insignia was originally approved for the 15th Signal (Service) Battalion on 13 December 1941. It was redesignated for the 15th Signal Service Regiment on 28 February 1942. The insignia was rescinded on 27 January 1959. It was reinstated, redesignated and amended to add a description for the 15th Signal Brigade on 11 July 1986. The insignia was amended to correct the description on 15 August 1986.

Source: The US Army Institute of Heraldry