SIP User's Manual 348 Document #: LTRT-68806
Mediant 2000 & TP-1610 & TP-260/UNI
7.3 Event Notification using X-Detect Header
The gateway supports the sending of notifications to a remote party notifying the
occurrence (or detection) of certain events on the media stream. Event detection and
notifications is performed using the X-Detect SIP message header, and only when
establishing a SIP dialog.
For supporting some events, certain gateway configurations need to be performed. The
table below lists the support event types (and subtypes) and the corresponding gateway
configurations, if required:
Table 7-1: Supported X-Detect Event Types
Events
Type Subtype
Required Configuration
AMD voice
automatic
silence
unknown
EnableDSPIPMDetectors = 1
AMDTimeout = 2000 (msec)
CPT SIT SITDetectorEnable = 1
UserDefinedToneDetectorEnable = 1
Note: Differentiation of SIT is not supported in 5.0.
CED (IsFaxUsed ≠0) or (IsFaxUsed = 0, and FaxTransportMode ≠0) FAX
modem VxxModemTransportType = 3
PTT voice-start
voice-end
EnableDSPIPMDetectors = 1
The X-Detect event notification process is as follows:
1. For IP-to-Tel or Tel-to-IP calls, the gateway receives a SIP request message (using
the X-Detect header) that the remote party wishes to detect events on the media
stream. For incoming (IP-to-Tel) calls, the request must be indicated in the initial
INVITE and responded to either in the 183 response (for early dialogs) or in the 200
OK response (for confirmed dialogs). For outgoing calls (Tel-to-IP), the request may
be received in the 183 (for early dialogs) and responded to in the PRACK, or received
in the 200 OK (for confirmed dialogs) and responded to in the ACK.
2. Once the gateway receives such a request, it sends a SIP response message (using
the X-Detect header) to the remote party, listing all supported events that can be
detected. The absence of the X-Detect header indicates that no detections are
available.
3. Each time the gateway detects a supported event, the event is notified to the remote
party, by sending an INFO message with the following message body:
• Content-Type: application/X-DETECT
• Type = [AMD | CPT | FAX | PTT…]
• Subtype = xxx (according to the defined subtypes of each type)
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