This corpus comprises 6,140 entries uttered by 265 speakers of different dialects, ages and various educational levels (144 males and 141 females), recorded over the mobile telephone network. The database comprises 8,109 Chinese digit strings. Speech samples are stored as a sequence of 16-bit 8kHz WAV for a total of 11.8 hours of speech. The total capacity of the data is 669 Mb. Each speaker read 25-30 items. Text files are stored in Unicode format. All data have been proofread manually. The transcriptions include non-speech markers (background noise, background speech, speaker sounds) as well as markers for mispronunciation, channel distortions, words left-out and duplicates. The corpus aims to be applied to the testing and telephone natural speech recognition system.