CUCM Alaw Prefer

System - > Region Information → Audio Codec Preference Lists

Copy the “Factory Default low loss” and call it “Factory Default low loss - alaw prefer” Edit this new preference list and move alaw codec above the ulaw codec and save

System → Service Parameters - Cisco CallManager

Apply from the dropdown box your new preference list “Factory Default low loss - alaw prefer”to the two settings:

Default Audio Codec List between Regions Required Field
Default Audio Codec List within Region Required Field