[Linphone-developers] Missing DTMF fmtp in 200 Ok message

[Jeroen van der Laan]

We're interfacing with a PBX that requires that we send a reply to a telephone event. the telephone event has a fmtp with DTMF information as follows:

Session Description Protocol

    Session Description Protocol Version (v): 0

    Owner/Creator, Session Id (o): 123 8000 8000 IN IP4 192.168.178.18

        Owner Username: 123

        Session ID: 8000

        Session Version: 8000

        Owner Network Type: IN

        Owner Address Type: IP4

        Owner Address: 192.168.178.18

    Session Name (s): SIP Call

    Connection Information (c): IN IP4 192.168.178.18

        Connection Network Type: IN

        Connection Address Type: IP4

        Connection Address: 192.168.178.18

    Time Description, active time (t): 0 0

        Session Start Time: 0

        Session Stop Time: 0

    Media Description, name and address (m): audio 23840 RTP/AVP 0 8 101

        Media Type: audio

        Media Port: 23840

        Media Protocol: RTP/AVP

        Media Format: ITU-T G.711 PCMU

        Media Format: ITU-T G.711 PCMA

        Media Format: DynamicRTP-Type-101

    Media Attribute (a): sendrecv

    Media Attribute (a): rtpmap:0 PCMU/8000

        Media Attribute Fieldname: rtpmap

        Media Format: 0

        MIME Type: PCMU

        Sample Rate: 8000

    Media Attribute (a): ptime:20

        Media Attribute Fieldname: ptime

        Media Attribute Value: 20

    Media Attribute (a): rtpmap:8 PCMA/8000

        Media Attribute Fieldname: rtpmap

        Media Format: 8

        MIME Type: PCMA

        Sample Rate: 8000

    Media Attribute (a): rtpmap:101 telephone-event/8000

        Media Attribute Fieldname: rtpmap

        Media Format: 101

        MIME Type: telephone-event

        Sample Rate: 8000

    Media Attribute (a): fmtp:101 0-15

        Media Attribute Fieldname: fmtp

        Media Format: 101 [telephone-event]

        Media format specific parameters: 0-15

Linphone replies with the folowing SDP:

Session Description Protocol

    Session Description Protocol Version (v): 0

    Owner/Creator, Session Id (o): jeroen 1252 1740 IN IP4 192.168.178.21

        Owner Username: jeroen

        Session ID: 1252

        Session Version: 1740

        Owner Network Type: IN

        Owner Address Type: IP4

        Owner Address: 192.168.178.21

    Session Name (s): Talk

    Connection Information (c): IN IP4 192.168.178.21

        Connection Network Type: IN

        Connection Address Type: IP4

        Connection Address: 192.168.178.21

    Time Description, active time (t): 0 0

        Session Start Time: 0

        Session Stop Time: 0

    Media Description, name and address (m): audio 7078 RTP/AVP 0 8 101

        Media Type: audio

        Media Port: 7078

        Media Protocol: RTP/AVP

        Media Format: ITU-T G.711 PCMU

        Media Format: ITU-T G.711 PCMA

        Media Format: DynamicRTP-Type-101

    Media Attribute (a): rtpmap:101 telephone-event/8000

        Media Attribute Fieldname: rtpmap

        Media Format: 101

        MIME Type: telephone-event

        Sample Rate: 8000

There is no fmtp for the telephone-event. This limtis the use of rfc2833 DTMF. Is there a way to enable this?

Best regards,

Jeroen van der Laan

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