UPD.
При рестарте asterisk'а в логах:
[2015-08-10 13:39:06] NOTICE[4780] res_odbc.c: Connecting mssql-asteriskcdrdb
[2015-08-10 13:39:06] WARNING[4780] res_odbc.c: res_odbc: Error SQLConnect=-1 errno=0 [unixODBC][FreeTDS][SQL Server]Unable to connect to data source
[2015-08-10 13:39:06] WARNING ...

