Specifications

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Cisco 1751 Router Software Configuration Guide
OL-1070-01
Syntax Description
Default
g729r8.
Command Mode
Dial-peer configuration.
Usage Guidelines
Use the codec command to define a specific voice coder rate of speech for a dial peer.
For toll quality, use g711alaw or g711ulaw. These values provide high-quality voice transmission, but
use a significant amount of bandwidth. For almost toll quality (and a significant savings in bandwidth),
use the g729r8 value.
If codec-command values for the VoIP peers of a connection do not match, the call fails.
This command only applies to VoIP peers.
Note Prior to Cisco IOS Release 12.0(5)T, g729r8 is implemented in the pre-IETF format;
thereafter it is implemented in the standard IETF format. Whenever new images, from
Release 12.0(5)T or later, interoperate with older versions of VoIP (when the g729r8
codec was not compliant with the IETF standard), users can hear garbled voices and
ringback on either end of the connection. To avoid this problem, configure the dial peers
with the g729r8 pre-ietf argument.
g711alaw G.711 A-Law 64,000 bits per second (bps).
g711ulaw G.711 U-Law 64,000 bps.
g723ar53 G.723.1 ANNEX-A 5,300 bps.
g723ar63 G.723.1 ANNEX-A 6,300 bps.
g723r53 G.723.1 5,300 bps.
g723r63 G.723.1 6,300 bps.
g726r16 G.726 16,000 bps.
g726r24 G.726 24,000 bps.
g726r32 G.726 32,000 bps.
g729br8 G.729 ANNEX-B 8,000 bps.
g729r8 G.729 8,000 bps.