In
telecommunications
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than tha ...
, a system that supports simultaneous voice and data (SVD) is one that can
transceive both voice and primary
data
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...
concurrently over one
PSTN
The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other el ...
modem
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more c ...
.
Background
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
A bearer channel is a DS-0 that carries call content i.e. one that does not carry signaling
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used a ...
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.
Types
* Digital Simultaneous Voice and Data, or DSVD, defined by the
ITU-T V.70 standard.
*
Analog Simultaneous Voice and Data, or ASVD, defined by the
ITU-T V.61 standard.
*
Data over signalling
Data over signalling (sometimes data over signaling) or DoS, is a technique in telecommunications in which primary data is sent over a signalling channel instead of the subscriber's bearer channel
A bearer channel is a DS-0 that carries call c ...
, or DoS, wherein data is multiplexed onto the signalling channel and voice is dedicated to the bearer channel.
*
Combined voice and data, wherein the data is multiplexed with voice onto the bearer channel.
See also
*
Multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a ...
*
Voice activity detection Voice activity detection (VAD), also known as speech activity detection or speech detection, is the detection of the presence or absence of human speech, used in speech processing. The main uses of VAD are in speech coding and speech recognition. I ...
References and notes
Telephony
Data transmission
{{telephony-stub