Data over signalling, or DoS, is a telecommunications term that refers to sending primary data

Data

The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

 over a signalling channel

Signalling (telecommunications)

In telecommunication, signaling has the following meanings:*the use of signals for controlling communications...

, instead of the subscriber's

User (telecommunications)

In telecommunications, a user is a person, organization, or other entity that employs the services provided by a telecommunication system, or by an information processing system, for transfer of information....

 bearer channel

Bearer channel

A bearer channel is a DS-0 that carries call content i.e. one that does not carry signaling.In the Common Channel Signaling scheme for telecommunications, signaling is sent out-of-band, while all other traffic rides bearer channels...

.

Background

Data over signalling was designed as a solution to the problem of transceiving simultaneous voice and data

Simultaneous voice and data

Simultaneous voice and data, or SVD, is a telecommunications term that refers to transceiving both voice and primary data concurrently over one PSTN modem. -Background:...

.

Data over signalling can be utilized when the signalling channel is either channel associated

Channel Associated Signaling

Channel Associated Signaling , also known as per-trunk signaling , is a form of digital communication signaling. As with most telecommunication signaling methods, it uses routing information to direct the payload of voice or data to its destination. With CAS signaling, this routing information is...

 or common

Common Channel Signaling

In telephony, Common Channel Signaling , in the US also Common Channel Interoffice Signaling , is the transmission of signaling information on a separate channel from the data, and, more specifically, where that signaling channel controls multiple data channels.For example, in the public switched...

. However, it is easier to implement when the signalling channel is channel associated, as the system does not have to demultiplex the data and signalling between multiple subscribers.

DoS was designed so that mobile telephony subscribers could maintain a voice session on their bearer channel while still accessing data related services, such as text messaging

Text messaging

Text messaging, or texting, refers to the exchange of brief written text messages between fixed-line phone or mobile phone and fixed or portable devices over a network...

.

See also

• Simultaneous voice and data
  Simultaneous voice and data
  Simultaneous voice and data, or SVD, is a telecommunications term that refers to transceiving both voice and primary data concurrently over one PSTN modem. -Background:...
  
  
• V.70
• V.61
  V.61
  ITU V.61 is a standard for Analog Simultaneous Voice and Data , a MODEM related standard for use over a POTS line or leased line.The can be downloaded free of charge in several languages.-See also:*V.70 Digital Simultaneous Voice and Data...