Telefonica's mailbox cannot do audio fallback when sending fax


#1

Hi!

In my mobile phone’s (provider: Telefonica) mailbox is a fax,
because: I sent it there myself. :slight_smile:
When I try to receive that fax via my DSL VoIP number (again: Telefonica),
I get an error and tcpdump tells me that the first reinvite is “not acceptable” and the second reinvite is a reason to say “BYE” (see appendix).

Is there a better solution than changing the extension.conf, so that my mailbox number is forced to be treated as non-T.38 (then it works fine and the mailbox says it uses a HP-OCMP)?

Thx.

Bye
Arne

appendix:

07:55:40.492031UTC
    213.20.127.40.5060 > 192.168.1.3.5060: SIP, length: 1272
        INVITE sip:43@192.168.1.3:5060 SIP/2.0
        CSeq: 1037909783 INVITE
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 619
        SIP/2.0 100 Trying
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 928
        SIP/2.0 200 OK
    213.20.127.40.5060 > 192.168.1.3.5060: [udp sum ok] SIP, length: 473
        ACK sip:43@192.168.1.3:5060 SIP/2.0
07:55:44.013262UTC
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 947
        INVITE sip:sgc_c@213.20.127.40;transport=udp SIP/2.0
        CSeq: 102 INVITE
        m=image 4330 udptl t38
        s=Asterisk PBX 15.0.0
        a=T38FaxMaxDatagram:1400
    213.20.127.40.5060 > 192.168.1.3.5060: [udp sum ok] SIP, length: 378
        SIP/2.0 100 Trying
        CSeq: 102 INVITE
    213.20.127.40.5060 > 192.168.1.3.5060: [udp sum ok] SIP, length: 386
        SIP/2.0 606 Not acceptable
        CSeq: 102 INVITE
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 470
        ACK sip:sgc_c@213.20.127.40;transport=udp SIP/2.0
        CSeq: 102 ACK
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 927
        INVITE sip:sgc_c@213.20.127.40;transport=udp SIP/2.0
        CSeq: 103 INVITE
        m=audio 15378 RTP/AVP 8 101
    213.20.127.40.5060 > 192.168.1.3.5060: [udp sum ok] SIP, length: 390
        SIP/2.0 487 Request terminated
        CSeq: 103 INVITE
    213.20.127.40.5060 > 192.168.1.3.5060: [udp sum ok] SIP, length: 423
        BYE sip:43@192.168.1.3:5060 SIP/2.0
        CSeq: 1037909784 BYE
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 470
        ACK sip:sgc_c@213.20.127.40;transport=udp SIP/2.0
        CSeq: 103 ACK
07:55:44.492357UTC
    192.168.1.3.5060 > 213.20.127.40.5060: [udp sum ok] SIP, length: 556
        SIP/2.0 200 OK
        CSeq: 1037909784 BYE