Its first complete transmission occurred on September 14, 1923, live commentary of the prize fight between Jack Dempsey and Luis Ángel Firpo from New York.

José Velasco captured the New York station's signal at Pachuca and relayed the information to Enrique W. Curtiss, who broadcast it over CYB.

The next day, the station held its inaugural concert, which included a message from Spanish king Alfonso XIII.

In 1929, actress Pura Córdoba founded a drama group devoted to performing radio plays, which laid down the foundation for the genre's success in Mexico.

Jorge Marrón, Julio Sotelo and Enrique W. Curtiss all started at XEB, which at this time was located at 665 kHz.

XEB increased to 100 kW of power, but it had trouble maintaining the transmitter as the war effort made finding replacement parts nearly impossible.

In April 1945, XEB was the first station to inform Mexican listeners of the death of U.S. President Franklin Delano Roosevelt, four minutes before its competitors.

That same year, it created a sports radio network, featuring popular personalities Julio Sotelo, Fernando Marcos and Cristino Lorenzo.

Never the less, high-profile stars including Miguel Prado, Blanca Estela Pavón and Raquel Moreno remained on XEB.

During this time, sports announcers like Óscar Esquivel and Ángel Fernandez joined the station, which became known as "Voz y expresión de México" the next year.