Polycom MGC Administrator Administrator's Manual page 487

For IVR Message Service (IVR enabled conferences), in the Attributes
drop-down list, select 8000Hz, 16Bit, Stereo.
7. To save this format, click the Save As button.
The Save As dialog box opens. Select the location where the format will
reside and type a name for the format, for example, PCM, and then click
OK.
The format name appears in the Name field.
8. Click OK.
The system returns to the Properties for Sound dialog box.
9. Click OK.
The system returns to the Sound–Sound Recorder dialog box.
10. To create a new recording, from the File menu, select New.
11. Click the Record button.
The system starts recording.
12. Start narrating the desired message.
13. For IVR Services, stop the recording anytime between 1 and 32 seconds
(which is the maximum duration allowed for an IVR voice message).
If the message exceeds 32 seconds, it will be automatically clipped to
exactly 32 seconds when converted into the MGC internal format file.
The audio message can be recorded in one of the following durations: 2,
4, 8, 16 and 32 seconds.
MGC Administrator's Guide
8-5