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Collaboration, Voice & AV · Foundational

Digital Signal 0 (DS0)

A single 64 kbps digital voice channel, the basic building block of T1, E1 and ISDN circuits.

Definition

A DS0 carries one PCM-encoded voice call: 8000 samples per second times 8 bits per sample equals 64 kbps. Twenty-four DS0s form a DS1 (T1) and thirty-two timeslots form an E1. Uncompressed G.711 voice is exactly one DS0 of payload, which is why G.711 is the default codec for TDM interworking.

Example

A PRI provides 23 DS0 bearer channels for simultaneous calls.

Exam tip

If asked why G.711 is 64 kbps, the answer is the 8 kHz Nyquist sampling rate times 8-bit samples, which is one DS0.

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