Audio configuration, Cisco confidential--first draft, Spa9x2 phone field reference – Linksys BUSINESS SPA922 User Manual

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Linksys SPA9x2 Phone Administration Guide

Cisco Confidential--First Draft

173

Ext Tab

SPA9x2 Phone Field Reference

Audio Configuration

A codec resource is considered as allocated if it has been included in the SDP codec list of an
active call, even though it eventually may not be the one chosen for the connection. So, if the
G.729a codec is enabled and included in the codec list, that resource is tied up until the end of
the call whether or not the call actually uses G.729a. If the G.729a resource is already allocated
and since only one G.729a resource is allowed per device, no other low-bit-rate codec may be
allocated for subsequent calls; the only choices are G711a and G711u. On the other hand, two
G.723.1/G.726 resources are available per device.

Therefore it is important to disable the use of G.729a in order to guarantee the support of two
simultaneous uses of the G.723/G.726 codecs.

Mini Certificate

Base64 encoded of Mini-Certificate concatenated with
the 1024-bit public key of the CA signing the MC of all
subscribers in the group.

Defaults to blank.

SRTP Private Key

Base64 encoded of the 512-bit private key per subscriber
for establishment of a secure call.

Defaults to blank.

Parameter

Description

Preferred Codec

Preferred codec for all calls. (The actual codec used in a call still
depends on the outcome of the codec negotiation protocol.)
Select one of the following: G711u, G711a, G726-16, G726-24,
G726-32, G726-40, G729a, or G723.

Defaults to G711u.

Use Pref Codec Only

To use only the preferred codec for all calls, select yes. (The call
fails if the far end does not support this codec.) Otherwise,
select no.

Defaults to no.

Second Preferred Codec

The second preferred codec when the preferred codec cannot
be used. If Use Pref Codec Only is enabled (set to yes), this
parameter is not used.

Defaults to Unspecified.

Third Preferred Codec

The third preferred codec when the preferred codec and
second preferred codec cannot be used. If Use Pref Codec Only
i
s enabled (set to yes), this parameter is not used.

Defaults to Unspecified.

Parameter

Description

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