[Asterisk-Users] RFC 2833 / Timestamp

[Gerard O'Rourke]

Hi,

We are using Asterisk for a h323 / SIP converter.
We are having problems when users enter DTMF quickly.

The reason for the problem is that the Timestamp Header field in the RTP
stream
for the 2 separate DTMF events are set at the same number.

Has anyone else had this problem and does anyone know if there is a fix for
it?

See below for trace:
Note how the Timestamp header is set to "24352" in both cases.
Our system ignores the first DTMF because of this.

Note: Cisco uses a much larger timestamp header than this ( a 4 digit HEX
number e.g. Timestamp: 1527784437
And never use the same Timestamp for separate DTMF events.

Rgs,
Gerard.



User Datagram Protocol, Src Port: 6934 (6934), Dst Port: 1686 (1686)
Real-Time Transport Protocol
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 .... = Extension: False
    .... 0000 = Contributing source identifiers count: 0
    1... .... = Marker: True
    .110 0101 = Payload type: Unknown (101)
    Sequence number: 33529
    Timestamp: 24352
    Synchronization Source identifier: 1497941844
RFC 2833 RTP Event
    Event ID: DTMF Two 2 (2)
    0... .... = End of Event: False
    .0.. .... = Reserved: False
    ..00 1010 = Volume: 10
    Event Duration: 0


User Datagram Protocol, Src Port: 6934 (6934), Dst Port: 1686 (1686)
Real-Time Transport Protocol
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 .... = Extension: False
    .... 0000 = Contributing source identifiers count: 0
    1... .... = Marker: True
    .110 0101 = Payload type: Unknown (101)
    Sequence number: 33531
    Timestamp: 24352
    Synchronization Source identifier: 1497941844
RFC 2833 RTP Event
    Event ID: DTMF Three 3 (3)
    0... .... = End of Event: False
    .0.. .... = Reserved: False
    ..00 1010 = Volume: 10
    Event Duration: 0


---------------
Gerard O'Rourke
Connectivity Technology Manager
V O X P I L O T
+353 1 209 1919