Digital Signal 0 (DS0) and Digital Signal 3 (DS3)

Digital Signal 0 (DS0) is a basic digital signalling rate of 64 kbit/s, corresponding to the capacity of one voice-frequency-equivalent channel.

Because of its fundamental role in carrying a single phone call, the DS0 rate forms the basis for the digital multiplex transmission 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 multiplexed together on higher capacity circuits. In this system, twenty-four (24) DS0s are multiplexed into a DS1 signal. Twenty-eight (28) DS1s are multiplexed into a DS3. When carried over copper wire, this is the well-known T-carrier system, with T1 and T3 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.


Digital Signal 3 (DS3) is a digital signal level 3 T-carrier. It may also be referred to as a T3 line.

* The data rate for this type of signal is 44.736 Mbit/s.
* This level of carrier can transport 28 DS1 level signals within its payload.
* This level of carrier can transport 672 DS0 level channels within its payload.

Usage
The level of transport or circuit is mostly used between telephony carriers, both wired and wireless.