Digium Asterisk Appliance 50 AA50 Administrator's Manual page 36

MWI Mode - This option allows the user to specify the type of Mes-
sage Waiting Indicator detection to be done on trunk (FXO) interfaces.
The options are none, which performs no detection, FSK which per-
forms Frequency Shift Key detection, or NEON which perform Neon
MWI dection. The default value is none.
Once you have made the configuration changes to your hardware which
you require, click Save Changes. A message will display letting you
know that in order for these changes to be completed, you must reboot
your AA50. Click Options on the left menu, select the Reboot tab, and
then click Reboot Now to reboot your appliance. Rebooting your AA50
will terminate any active calls.
Release 1.20
Chapter 3: Telephone System Configuration
Digium, Inc. Page 36