AudioCodes Mediant 4000 SBC, User Manual

Page: 205 / 1037

CHAPTER 15 Media
Mediant 4000 SBC | User's Manual
Event Detection and Notification using X-Detect Header
The device can detect certain events in the media stream and notify of their detection to a remote
application server, using the SIP X-Detect header. The request for event notification is done by the
application server when establishing a SIP dialog (i.e., INVITE message) or during an already
established call using a re-INVITE message. The device can detect the following event types:
■ Answering Machine Detection (AMD): Detects events that are related to the AMD feature.
AMD detects whether an answering machine or live voice has answered the call. It can also be
used to detect silence, or the beep sound played by an answering machine to indicate the end
of the greeting message after which a voice message can be left. For more information on
AMD, see
Answering Machine Detection (AMD) .
■ Call Progress Tone (CPT): Detects whether a specific tone, defined in the installed CPT file is
received from the call. It can be used to detect the beep sound played by an answering
machine (as mentioned above), and the busy, reorder and ring tones.
● Event detection on SBC calls for CPT is supported only for calls using the G.711
coder.
The X-Detect header is used for event detection as follows:
■ X-Detect header in the INVITE message received from the application server requesting a
specific event detection:
X-Detect: Request=[event type to detect]
■ X-Detect header in the SIP response message -- SIP 183 (for early dialogs) or 200 OK (for
confirmed dialogs) -- sent by the device to the application server specifying which of the
requested events it can detect (absence of the X-Detect header indicates that the device
cannot detect any of the events):
X-Detect: Response=[supported event types]
■ Each time the device detects the supported event, it sends an INFO message to the remote
party with the following message body:
Content-Type: Application/X-Detect
Type = [event type]
Subtype = [subtype of each event type]
The table below lists the event types and subtypes that can be detected by the device. The text
shown in the table are the strings used in the X-Detect header. The table also provides a summary
of the required configuration.
For SBC calls, event detection is enabled using the IPProfile_SBCHandleXDetect parameter in the
IP Profiles table (see
Configuring IP Profiles ).
Table 15-1: Supported X-Detect Event Types
Event
Type
Subtype Description and Required Configuration
AMD ■ Voice (live voice)
■ Automata (answering
machine)
Event detection using the AMD feature. For more
information, see
Answering Machine Detection (AMD) .
- 172 -