Simplified Message Desk Interface - Session Initiation Protocol
Simplified Message Desk Interface (SMDI) is a protocol that defines the interface between a phone system and a voice mail system. It was developed by Bell Labs. It is used to provide the voice mail system the information it needs to process the call. Each time a call is sent to the voice mail a message is sent using SMDI over a serial interface that identifies the line, the type of call and Calling/Called party numbers. The SMDI protocol also specifies a method for turning Message Waiting Indication (MWI) on and off on individual telephone lines.
Message Format
<CR><LF>MDXXXLLLLT<0×20>YYYY<0×20><CR><LF><^Y>
<CR> Carriage Return
<LF> Line Feed
MDXXX Message Desk. This is a 3 digit field (usually 001)
LLLL Logical Terminal Number (0001 - 4096)
T Reason Code (D equals Direct Call, A equals All Calls Forwarded, B equals Busy Call, U equals Unknown)
<0×20> Space
YYYY Calling Party Number
<CR> Carriage Return
<LF> Line Feed
<^Y> End
MWI Format
OP Operate Message Waiting Indicator (Turn On)
OP:MWI<0×20>XXXX!<EOT>
<0×20> Space
XXXX Extension Number
<EOT> End of Transmission
RMV:MWI<0×20>XXXX!<EOT>
RMV Operate Message Waiting Indicator (Turn Off)
<0×20> Space
XXXX Extension Number
<EOT> 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)
<CR><LF>MD0010007D<0×20>3500<0×20><CR><LF><^Y>
See also
- Session Initiation Protocol
Links
- Voz sobre IP - Wikipédia Voz sobre IP, também chamado VoIP, telefonia IP, telefonia Internet, telefonia em banda larga e . O suporte de envio de fax sobre VoIP ainda é limitado.
- VOIP: For Home And Business Use VOIP is a new communications technology that allows local calls from any location, find out how it can be useful for you.
- What is VoIP? [Voice and Unified Communications] - Cisco Systems VoIP and IP telephony are becoming increasingly popular with large corporations and consumers alike. For many people, Internet Protocol (IP) is more than
- Understanding VOIP If you are new to VOIP, here is a description of how this new technology works.
- Voice-Over-Internet Protocol An overview of VoIP from the Federal Communications Commission. With news, FAQs, factsheets, and findings.
- VoIP Definition: TechEncyclopedia from TechWeb VoIP - (Voice Over IP) A digital telephone service that uses the public Internet as well as private backbones instead of the traditional telephone network.