...

[asterisk]
enabled => yes
dsn => your-configured-dsn-name
username => your-database-username
password => insecurepassword
pooling => no
limit => 1
pre-connect => yes

Then start up Asterisk and assuming res_odbc loads properly on the CLI you can use odbc show to verify connectivitya DSN is configured and shows up:

rnewton-office-lab*CLI> odbc show
ODBC DSN Settings
-----------------
  Name:   asterisk
  DSN:    your-configured-dsn-name
    Last connection attempt: 1969-12-31 18:00:00
  Pooled: No
  Connected: Yes

To verify the connection works you should use func_odbc or something similar to query the data source from Asterisk.

Troubleshooting

If you don't have the odbc command at the CLI, check that

...