the called party number is to select which voicemail greeting to play for the call. MWI format OP:MWI<0x20>XXXX!<EOT> Meaning of the individual segments: - Operate message-waiting indicator (turn on) - space - extension number - end-of-transmission character RMV:MWI<0x20>XXXX!<EOT> - remove message-waiting indicator (turn off) - space - extension number - End of Transmission Example This is an example of a direct call from extension 3500. It was presented to the voice messaging system on LTN 0007 (port 7). This would be someone calling from their extension to pick up their voicemail and thus would likely ask for sign-on credentials, such as a PIN. <CR><LF>MD0010007D<0x20>3500<0x20><CR><LF><^Y> See also Session Initiation Protocol Analog Display Services Interface References External links Cisco Call Manager Use of SMDI Asterisk, an example open source PBX that supports SMDI A Simplified Message Desk Interface (SMDI) Primer from Dialogic Telephony Voicemail