yum install asterisk-odbc

mv /etc/asterisk/cdr_mysql.conf /etc/asterisk/cdr_mysql.old

Create the following, note the PASSWORD fields need to match the ASTERISKUSER password from cdr_mysql.old

/etc/odbc.ini

[MySQL-cdr]
driver=MySQL
server=localhost
database=asteriskcdrdb
option=3

-----------------------------------------

/etc/odbcinst.ini

[MySQL]
driver=/usr/lib/odbc/libmyodbc.so
setup=/usr/lib/odbc/libodbcmyS.so
fileusage=1

-----------------------------------------

/etc/asterisk/res_odbc.conf

[MySQL-cdr]
enabled => yes
dsn => MySQL-cdr
username => asteriskuser
password => PASSWORD
pre-connect => yes

-----------------------------------------

/etc/asterisk/cdr_odbc.conf

[global]
dsn=MySQL-cdr
username=asteriskuser
password=PASSWORD
loguniqueid=yes