Simultaneous voice and data, or SVD, is a telecommunications term that refers to transceiving both voice and primary data essentially simultaneously.
Before telecommunication networks began to support data related services, the bearer channel was dedicated solely to voice information. When support for data related services was originally released, the bearer channel
was switched between being dedicated to voice information or dedicated to primary data information, depending on the subscriber's needs at any given time. Eventually, support for simultaneous voice and data transmission was added to modems
and mobile devices, to enable subscribers to use voice and data services at the same time.
References and notes