Polycom Version 1.4.x 17 - Manual (Page 52)

Administrator Guide - SoundPoint ® IP / SoundStation ® IP Features
44 Copyright © 2004 Polycom, Inc.
3.3.7 Acoustic Echo Cancellation (AEC)
The phone employs advanced acoustic echo cancellation for hands-free operation.
Both linear and non-linear techniques are employed to aggressively reduce echo yet
provide for natural full-duplex communication patterns.
3.3.8 Audio Codecs
The following table summarizes the phone’s audio codec support:
Algorithm MIME Type Ref. Bit Rate
Sample
Rate
Frame Size
Effective
audio band-
width
G.711 µ-law PMCU RFC
1890 64 Kbps 8 Ksps 10ms - 80ms 3.5KHz
G.711a-law PCMA RFC
1890 64 Kbps 8 Ksps 10ms - 80ms 3.5KHz
G.729AB G729 RFC
1890 8 Kbps 8 Ksps 10ms - 80ms 3.5KHz
SID CN RFC
3389 N/A N/A N/A N/A
RFC 2833 phone-event RFC
2833 N/A N/A N/A N/A
Central
(boot
server)
Configuration file:
ipmid.cfg Specify codec priority, preferred payload sizes, and jitter
buffer tuning parameters.
For more information, see
•
4.6.1.6.1.1 Codec Preferences <preferences/> on
page 79, and
• 4.6.1.6.1.2 Codec Profiles <profiles/> on page 79.
Local
Web Server
(if enabled) Specify codec priority, preferred payload sizes, and jitter
buffer tuning parameters.
Navigate to: http://<phoneIPAddress>/coreConf.htm#au
Changes are saved to local flash and backed up to <Ethernet
address>-phone.cfg on the boot server. Changes will per-
manently override global settings unless deleted via the
Reset User Settings menu selection.
Local Phone User
Interface None.