> Is there a way to specify the codec in the dial plan for an outbound
> call using IAX?
Sure, just use something like this in iax.conf:
[diamondcard]
type=peer ; outgoing calls only
host=1.2.3.4
username=myuserid
secret=mypassword
disallow=all
allow=gsm
Then in your Dial statement, simply refer to the context.
If you're not sure how to construct that dial statement, do a
show application dial
from the CLI. It should look something like:
exten => _72.,3,Dial(IAX2/myuserid@diamondcard/${EXTEN:2})
The above is just one way to do it.