simultaneous voice and data (SVD)

In the 1990s, various methods were developed to reduce telecommunications costs. These methods include simultaneous transmission of voice and data, Simultaneous Voice and Data (SVD), or data transmission during pauses in speech, Digital Speech Interpolation( DSI).

Simultaneous Voice and Data is available in the versions Analog Simultaneous Voice and Data( ASVD) and Digital Simultaneous Voice and Data( DSVD).

All of these methods were developed before the liberalization of the telecommunications market and are obsolete insofar as flat rates did not exist at that time. Analog Simultaneous Voice and Data (ASVD) was standardized by the International Telecommunication Union ( ITU) under V.61, Digital Simultaneous Voice and Data (DSVD) under V.70.