If your organization's voice mail server does not support KPML over SIP, you should configure Early Media Negotiation on the Telephony Connector to force the Cisco Unified Communications Manager to use a hardware MTP resource to convert the SIP-notify messages to RFC2833 before the messages reach your organization's voice mail server.

If your organization uses Cisco Unity for voicemail, leave the "Early Media Negotiation" box unchecked on the Telephony Connector and configure a SCCP integration between the Cisco Unified Communications Manager and the Cisco Unity.