Cisco 521SG Administration Guide - Page 31

Getting Started Ensuring Voice Quality 1 Number 723646 Option 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 *. Ensuring Voice Quality 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 MOS G.711 (A-law and u-law) G.726 Very low complexity. Supports uncompressed 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. 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. 4.5 4.1 (32 kbps) G.726 is supported only for 32 kbps on the Cisco SPA525G or Cisco SPA525G2. Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide 30