ITU-T V.70-1996
在GSTN或点对2线租用电话型电路上同时传输数据和数字编码语言信号的规程
Procedures for the Simultaneous Transmission of Data and Digitally Encoded Voice Signals over the GSTN or over 2-Wire Leased Point-to-Point Telephone Type Circuits - Series V: Data Communication over the Telephone Network Transmission Quality and Maintena