Codecs Page 295 of 910
IP Line Description, Installation and Maintenance
The G.729AB codec is selected, as it is the first in the order of preference of
the BB codecs. The G.723.1 codec does not get registered.
Example 2
A user configures three codecs:
1G.711 mu-law codec with a 20 msec payload
2G.729A codec with 30 msec payload
3G.723.1 codec with a 30 msec payload
The following five codecs are actually registered:
1G.711 mu-law (20 msec)
2G.711 a-law (20 msec)
3G.729A (30 msec)
4T.38
5G.711 Clear Channel
The G.729A codec is selected, as it precedes the G.723.1 codec in the order
of preference of the “best bandwidth” codecs.

Voice Gateway codec registration

The Voice Gateway registers codecs for the gateway channels as follows:
• G.711 a-law and G.711 mu-law are always registered.
• T.38 and G.711 Clear Channel fax codecs are always registered. G.711
Clear Channel is used for IP Trunk connections to BCM, which does not
support T.38 fax.
• A minimum of two codecs are registered if only G.711 was configured.
• A maximum of four codecs can be registered - the G.711 a-law and
mu-law for BQ codec, and some BB codecs (defined by the following
rules).
— If the G.729A codec is configured, only the G.729A codec is
registered with the Call Server.