cross-licensing agreements were concluded between a series of companies holding key patents, and on July 1, 1920, AT&T signed a comprehensive agreement with GE. These agreements in effect assigned dominance in specified areas of the radio industry to individual participating companies, which eventually would meet with anti-trust challenges. In addition, conflicting interpretations of some of the pact's clauses by the signatories would lead to numerous disputes, especially between AT&T and the other participants, known collectively as the "radio group". On December 1, 1921, the U.S. Department of Commerce, which regulated radio at this time, adopted a regulation formally establishing a broadcasting station category, which set aside the wavelength of 360 meters (833 kHz) for entertainment broadcasts, and 485 meters (619 kHz) for market and weather reports. AT&T soon recognized that it had the technical expertise and patent rights needed to play an important, and possibly dominant, role in the broadcasting industry. A December 1921 memo prepared by two AT&T engineers proposed that the company construct a nationwide radio network, using the company's longlines to connect together individual stations. They also noted that "this service would enable the national and local advertisers, industrial institutions of all kinds, and even individuals if they desire, to send forth information and advertising matter audibly to thousands". AT&T moved quickly to start implementing this plan, and on February 11, 1922, formally announced its intention to develop a "national chain of radio transmitting stations". A key component was the construction by AT&T of a well equipped New York City station. In early 1922 an experimental station, 2XY, was built atop the AT&T "Long Lines" building at 24 Walker Street. On April 29, 1922, the Walker Street station was issued a broadcasting station license, for operation on 360 meters, with the call sign of WBAY. On May 19 a second New York City broadcasting station, also on 360 meters, was licensed to the Western Electric Company, an AT&T subsidiary located at 463 West Street, with the call letters WDAM. Ten days later, this call sign was changed to WEAF. All of these call signs were randomly assigned from a sequential roster of available call letters, although at the time it was noted that WEAF matched the entrance artwork at AT&T headquarters at 195 Broadway, which depicted the four classical elements of water, earth, air and fire. The original plan was that AT&T would not originate any programming