Ensuring Voice Quality; Supported Codecs - Cisco 521SG - Unified IP Phone VoIP Administration Manual

Getting Started

Ensuring Voice Quality

Ensuring Voice Quality
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide
Number Option
723646 Enable or disables access to the administrative (admin) login on the
configuration utility. Press 1 to enable or 0 to disable, then press #.
To save, press 1; to review, press 2; to re-enter, press 3; to exit, press *.
Voice quality perceived by the subscribers of the IP Telephony service should be
indistinguishable from that of a PSTN.

Supported Codecs

The table shows the codecs (voice compression algorithms) supported by
Cisco SPA IP phones. The Mean Opinion Score (MOS) measures the voice quality
by using a scale of 1–5, where 1 is the lowest quality and 5 is the highest quality.
Codec Complexity and Description
G.711 (A-law Very low complexity. Supports uncompressed
and u-law) 64 kbps digitized voice transmission at one to ten
5ms voice frames-per-packet. This codec
provides the highest voice quality and uses the
most bandwidth of any of the available codecs.
G.726 Low complexity. Supports compressed 16, 24,
32, or 64 kbps digitized voice transmission at
one to ten 10ms voice frames per packet. When
no static payload value is assigned per
RFC-1890, Cisco SPA IP phones can support
dynamic payloads for G.726.
G.726 is supported only for 32 kbps on the
Cisco SPA525G or Cisco SPA525G2.
1
MOS
4.5
4. 1
(32 kbps)
30