Sit Event Detection - AudioCodes Mediant 1000B User Manual

14.4.1 SIT Event Detection

The device can detect and report the following Special Information Tones (SIT) types from
the PSTN:

SIT-NC (No Circuit found)

SIT-IC (Operator Intercept)

SIT-VC (Vacant Circuit - non-registered number)

SIT-RO (Reorder - System Busy)
There are additional three SIT tones that are detected as one of the above SIT tones:

The NC* SIT tone is detected as NC

The RO* SIT tone is detected as RO

The IO* SIT tone is detected as VC
The device can map these SIT tones to a Q.850 cause and then map them to SIP 5xx/4xx
responses,
SITQ850CauseForIC, SITQ850CauseForVC, and SITQ850CauseForRO.
Table 14-2: Special Information Tones (SITs) Reported by the device
Special Description
Information
Tones (SITs)
Name
NC1 No circuit found
IC Operator intercept
VC Vacant circuit (non
registered number)
RO1 Reorder (system
busy)
NC* -
RO* -
IO* -
The following example shows a SIP INFO message sent by the device to a remote
application server notifying it that SIT detection has been detected:
INFO sip:5001@10.33.2.36 SIP/2.0
Via: SIP/2.0/UDP 10.33.45.65;branch=z9hG4bKac2042168670
Max-Forwards: 70
From: <sip:5000@10.33.45.65;user=phone>;tag=1c1915542705
To: <sip:5001@10.33.2.36;user=phone>;tag=WQJNIDDPCOKAPIDSCOTG
Call-ID: AIFHPETLLMVVFWPDXUHD@10.33.2.36
CSeq: 1 INFO
Contact: <sip:2206@10.33.45.65>
Supported: em,timer,replaces,path,resource-priority
Content-Type: application/x-detect
Content-Length: 28
Type= CPT
SubType= SIT-IC
User's Manual
using the parameters
First Tone
Frequency
Duration
(Hz)
985.2
913.8
985.2
913.8
913.8
985.2
913.8
206
Mediant 1000B Gateway & E-SBC
SITQ850Cause,
Second Tone
Frequency
Duration
(ms) (Hz) (ms)
380 1428.5 380
274 1370.6 274
380 1370.6 274
274 1428.5 380
380 1370.6 380
274 1370.6 380
380 1428.5 274
Document #: LTRT-27055
SITQ850CauseForNC,
Third Tone
Frequency
Duration
(Hz) (ms)
1776.7 380
1776.7 380
1776.7 380
1776.7 380
1776.7 380
1776.7 380
1776.7 380