"New Stations: Commercial Land Stations", Radio Service Bulletin, September 1, 1921. Beginning with the introduction of U.S. radio station licensing in late 1912, it had been the practice to assign call signs starting with "K" in the west and "W" in the east. The original boundary line was located along the Texas-New Mexico border, and it wasn't until the shift in early 1923 to the Mississippi River that new Texas stations received K instead of W call signs.
WRR August 5, 1921 license, Limited Commercial license, serial #213, issued to the City of Dallas Police and Fire Signal Department for a one year period.
WRR March 13, 1922 license Limited Commercial license, serial #213, issued to the City of Dallas on March 13, 1922, for a 3 month period for broadcasting on 360 and 485 meters.
