Specifications

Legacy Integration
Planning and Installation Guide 14 – 7
SMDI Protocol Support
The ShoreTel 6.1 product supports the SMDI protocol, enabling seamless integration of
ShoreTel equipment with legacy phone systems and enabling a smooth migration
toward an all-IP telephony solution.
A little history...
The SMDI protocol evolved at a time when voice mail services and PBX services were
provided by separate physical devices. Over the years, manufacturers have managed to
offer both PBX and voice mail services within a single device, and the need for SMDI
has diminished. However, the protocol can still be useful in situations where newer
equipment will be integrated into a network of older devices.
How it works...
SMDI enables the separate devices that provide PBX and voice mail services to share
information over an out-of-band serial cable connection. The PBX shares information
with the voice mail system about incoming calls. The following information is passed
to the voice mail system:
• who the call is from
• where the call is going (i.e. user extension)
• the reason the call is going to voice mail instead of being answered
In response, the voice mail system returns a notification to the PBX that a message was
left on the voice mail server. The PBX system then uses this information to alert the
user by turning on the "message waiting" light on his or her phone.
Configurations of integrated equipment
With SMDI support, there are essentially two possible ways the ShoreTel and legacy
equipment can be configured:
External Voice Mail Configuration – The legacy system provides voice mail services
while the ShoreTel 6.1 system acts as the PBX.
ShoreTel VoiceMail Configuration – The ShoreTel system provides voice mail services
while the legacy system acts as the PBX.