Ensuring Voice Quality; Supported Codecs - Cisco SPA942 - - IP Phone Administration Manual

6

Ensuring Voice Quality

118
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
Regional
configure it on the
Defaults to 397@-19,507@-19;15(0/2/0,.2/. 1 /1,. 1 /2. 1 /2)
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.
Configuring Security, Quality, and Network Features
Call Progress Tones
web page under
Cisco SPA and Wireless IP Phone Administration Guide
Ensuring Voice Quality
.