Cisco SPA525G Administration Guide - Page 120

6 Configuring Security, Quality, and Network Features Ensuring Voice Quality The phone can be configured for secure provisioning using the factory-installed security certificate. To determine if the Client Certificate is installed on the phone: • SPA9X2: Press the Setup button and select Product Info. Scroll to Client Cert. • SPA525G: Press the Setup button and select Status. Select Product Information. Scroll to Certificate. • WIP310: Log in to the web administration interface. In the Info tab, under Product Information, certificate information is listed in the Client Certificate field. Secure Call Indication Tone This tone is played when a call has been successfully switched to secure mode. It should be played only for a short while (less than 30 seconds) and at a reduced level (less than -19 dBm), so it does not interfere with the conversation. You can configure it on the Regional web page under Call Progress Tones. Defaults to 397@-19,507@-19;15(0/2/0,.2/.1/1,.1/2.1/2) Ensuring Voice Quality Voice quality perceived by the subscribers of the IP Telephony service should be indistinguishable from that of the PSTN. Cisco IP phones support several codecs. See: • "Supported Codecs" section on page 118 • "Bandwidth Requirements" section on page 120 • "Factors Affecting Voice Quality" section on page 121 Supported Codecs Negotiation of the optimal voice codec sometimes depends on the ability of the Cisco IP Phone to "match" a codec name with the far-end device/gateway codec name. Cisco IP phones allow the network administrator to individually name the various codecs that are supported such that the correct codec successfully negotiates with the far-end equipment. Note that Cisco IP phones support voice codec priority. You can select up to three preferred codecs. 118 Cisco SPA and Wireless IP Phone Administration Guide