Simultaneous Transmission of Data and Other Signals
Applies to V.60–V.99
- V.61 Analog Simultaneous Voice and Data (ASVD)
- V.70 Digital Simultaneous Voice and Data (DSVD)
- V.80: videoconferencing. It is generally compatibilized with H.324 standard point-to-point video telephony over regular phone lines.
- V.90 is an ITU-T recommendation for a modem, allowing 56 kbit/s download and 33.6 kbit/s upload. It replaced two vendor standards (K56flex and X2) and was designed to allow modems from both prior standards to be flash upgraded to support it. It was developed between March 1998 and February 1999. It is also known as V.Last as it was anticipated to be the last standard for modems operating near the channel capacity of POTS lines to be developed. V.90 is generally used in concert with the V.42bis compression standard. A follow-on standard, V.92, was developed later in 1999 to replace V.90.
- V.92 is an ITU-T recommendation, titled Enhancements to Recommendation V.90, that establishes a modem standard allowing 56 kbit/s download, 48 kbit/s upload rates, and the new V.44 compression method. V.92 was first presented in August 1999. It is intended to succeed the V.90 standards. With V.92, PCM is used for both the upstream and downstream connections; previously 56K modems only used PCM for downstream data.
Read more about this topic: List Of ITU-T V-Series Recommendations
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