Polycom RMX 1500 Administrator's Manual page 551

the participants' names for playback when the participants join and
leave a conference.
When the system flag
IVR_ROLL_CALL_USE_TONES_INSTEAD_OF_VOICE is set to
YES, the system does not playback the Roll Call names when
participants enter or exit the conference. If the voice messages are
replaced with tones, the system will play these tones instead.
19 To enable the Roll Call feature, select the Enable Roll Call check box.
20 To assign the audio file to the message type, in the Message File
column, click the appropriate table entry. An arrow is displayed in
the Message File column.
If the Roll Call option is enabled, you must assign the appropriate audio files to
all message types.
Polycom RMX 1500/2000/4000 Administrator's Guide
15-19