Digital Signal 0

Digital Signal 0 (DS0) is a basic digital signaling rate of 64 kilobits per second (<a href="/facts/Kbit/s/Nv9VoT7T">kbit/s</a>), corresponding to the capacity of one analog <a href="/facts/Voice-frequency/XTQ6l9zo">voice-frequency</a>-equivalent <a href="/facts/Communication_channel/MtlxEShV">communication channel</a>. The DS0 rate, and its equivalents E0 in the <a href="/facts/E-carrier/h0MXcgXN">E-carrier</a> system and T0 in the <a href="/facts/T-carrier/tCsEdK72">T-carrier</a> system, form the basis for the digital multiplex <a href="/facts/Transmission_(telecommunications)/33zk8a0A">transmission</a> hierarchy in telecommunications systems used in North America, Europe, Japan, and the rest of the world, for both the early <a href="/facts/Plesiochronous/sf8YGV07">plesiochronous</a> systems such as <a href="/facts/T-carrier/tCsEdK72">T-carrier</a> and for modern synchronous systems such as <a href="/facts/Synchronous_Digital_Hierarchy/G3LgtGS6">SDH</a>/<a href="/facts/SONET/G3LgtGS6">SONET</a>.
The DS0 rate was introduced to carry a single digitized voice call. For a typical phone call, the audio sound is digitized at an 8 <a href="/facts/KHz/6Wshj5qm">kHz</a> sample rate, or 8000 samples per second, using 8-bit <a href="/facts/Pulse-code_modulation/5gdfjtH3">pulse-code modulation</a> for each of the samples. This results in a data rate of 64 <a href="/facts/Kbit/s/Nv9VoT7T">kbit/s</a>.
Because of its fundamental role in carrying a single phone call, the DS0 rate forms the basis for the digital multiplex <a href="/facts/Transmission_(telecommunications)/33zk8a0A">transmission</a> hierarchy in telecommunications systems used in North America. To limit the number of wires required between two involved in exchanging voice calls, a system was built in which multiple DS0s are <a href="/facts/Multiplexed/YE7hK8cw">multiplexed</a> together on higher capacity circuits. In this system, twenty-four (24) DS0s are multiplexed into a <a href="/facts/Digital_Signal_1/cghJPRpQ">DS1</a> signal. Twenty-eight (28) DS1s are multiplexed into a <a href="/facts/Digital_Signal_3/hfmvrz2m">DS3</a>. When carried over copper wire, this is the well-known <a href="/facts/T-carrier/tCsEdK72">T-carrier</a> system, with <a href="/facts/Digital_Signal_1/cghJPRpQ">T1</a> and <a href="/facts/Digital_Signal_3/hfmvrz2m">T3</a> corresponding to DS1 and DS3, respectively. 
Besides its use for voice communications, the DS0 rate may support twenty 2.4 kbit/s channels, ten 4.8 kbit/s channels, five 9.67 kbit/s channels, one 56 kbit/s channel, or one 64 kbit/s clear channel.
E0 (standardized as <a href="/facts/G.703/IxQPRM1e">ITU G.703</a>) is the European equivalent of the North American DS0 for carrying a single voice call. However, there are some subtle differences in implementation. Voice signals are encoded for carriage over E0 according to <a href="/facts/G.711/kopBvF25">ITU G.711</a>. Note that when a T-carrier system is used as in North America, <a href="/facts/Robbed_bit_signaling/BaGvyf9r">robbed bit signaling</a> can mean that a DS0 channel carried over that system is not an error-free bit-stream. The <a href="/facts/Out-of-band_signaling/6d4zgUj7">out-of-band signaling</a> used in the European E-carrier system avoids this.

Digital Signal 0 open-in-new

Digital Signal 0