Data over signalling (sometimes data over signaling) or DoS, is a technique 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 ...

in which 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 ...

is sent over a signalling channel instead of the subscriber's

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 ...

Background

Data over signalling was designed as a solution to the problem of transceiving simultaneous voice and data. Data over signalling can be utilized when the signalling channel is either channel associated or common. 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.

References

Telecommunications techniques Data transmission Telephony {{telephony-stub