Lucent Technologies Octel Unified Messenger, Planning Manual

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Octel Unified Messenger Concepts & Planning Guide
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Audio encoding formats
Octel Unified Messenger supports the following audio encoding formats:
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ADPCM audio encoding format. This is a high quality audio
encoding algorithm with a coding rate of 32 kilobit per second.
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Global System for Mobile Communications (GSM) 6.10 audio
encoding format. This audio encoding format has a coding rate of
approximately 13 kilobit per second.
GSM has the following benefits:
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Voice messages using GSM only use 40% of the storage
space compared with ADPCM messages. This reduces the
network bandwidth and storage requirements. It has a more
significant impact if a high proportion of subscribers use
Octel Unified Messenger through slow network connections.
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The GSM audio compression manager codec is available on
all Windows desktops. Voice messages recorded using Octel
Unified Messenger and sent to non-Unified Messenger users
can be played back using Microsoft Sound Recorder on a
multimedia-equipped PC without requiring any additional
software.
System administrators decide whether to use GSM or ADPCM format by
voice mail domain in Voice Mail System Configuration.
Important information for Octel Unified Messenger subscribers
upgrading from earlier releases
The selection of GSM as the preferred audio format for existing
installations should be carefully considered. Octel Unified Messenger
releases earlier than release 3.0 do not support the GSM format.
Consequently, any voice messages encoded using GSM format cannot be
played back by earlier releases of Octel Unified Messenger. System
administrators should ensure their system uses ADPCM only until all
Octel Unified Messenger components throughout their enterprise are
updated to Octel Unified Messenger 3.0.
When changing to GSM, all client systems need to be updated with the
new configuration information. This is achieved by using Octel Unified
Messenger Options to connect to an Octel Unified Messenger voice
server. Until subscribers update their desktops, they will continue to send
voice messages in ADPCM format.