The method includes steps: receiving dual-tone multifrequency code sent from communication terminal in sequence; based on relation between interval time length of received adjacent dual-tone multifrequency codes and prearranged interval time length to determine dual-tone multifrequency code set; based on dual-tone multifrequency code set to determine corresponding character. The invention also discloses a digit reception device, and application system at network side. Using current communication network and communication terminal, the invention implements inputting characters, and network side carries out receiving and parsing operation. Thus, application at network side can receive information of multiple characters input from user so as to raise flexibility and usability.