[asterisk-users] Asterisk 11 with t38modem 2.0: "488 Not acceptable here"

[Larry Moore]

My 2 cents worth.

Turn off faxdetect in the peer configuration for Asterisk.

Failing that, try the Fax Gateway feature in Asterisk 11 to Hylafax 
listening on an IAX2 channel.

Larry.

On 24/01/2013 6:32 AM, Carsten Maass wrote:
> Hello all,
>
> we do have a problem here with Asterisk 11 talking T.38 to a t38modem
> 2.0. The callflow is:
>
> ISDN PRI --> Berofix (10.1.1.150) --> Asterisk (10.1.1.148) --> t38modem
> (10.1.1.148) --> Hylafax [1]
>
> Although the call gets connected, both parties are unable to negotiate
> the audio codecs:
>
> [2013-01-23 21:59:57] VERBOSE[8805][C-00000000] chan_sip.c: Got T.38
> offer in SDP in dialog 237c0a65027630cd0c8bf2e70b5b3dc7 at 10.1.1.148:5060
> [2013-01-23 21:59:57] VERBOSE[8805][C-00000000] chan_sip.c:
> Capabilities: us - (alaw), peer -
> audio=(nothing)/video=(nothing)/text=(nothing), combined - (nothing)
> [2013-01-23 21:59:57] VERBOSE[8805][C-00000000] chan_sip.c: Non-codec
> capabilities (dtmf): us - 0x1 (telephone-event|), peer - 0x0 (nothing),
> combined - 0x0 (nothing)
> [2013-01-23 21:59:57] VERBOSE[8805][C-00000000] chan_sip.c: Got T.38
> Re-invite without audio. Keeping RTP active during T.38 session.
>
> which results in a "SIP/2.0 488 Not acceptable here" from the Asterisk
> and the call gets disconnected.
>
> Asterisk full log with SIP trace is at http://pastebin.com/NNr6BTdp
>
> This looks a lot like
> https://issues.asterisk.org/jira/browse/ASTERISK-15596 which doesn't
> seems to be solved by now.
>
> Is this still a known issue in Asterisk 11? What can I do to make
> Asterisk 11 play nice with t38modem v2.0?
>
>
> Environment:
> --------------
> Red Hat Enterprise Linux Server release 6.3 (Santiago)
>
> Linux myhost.mydomain.local 2.6.32-279.19.1.el6.x86_64 #1 SMP Sat Nov 24
> 14:35:28 EST 2012 x86_64 x86_64 x86_64 GNU/Linux
>
> T38Modem Version 2.0.0
>   (OPAL-3.9.0/3.9beta0, PTLIB-2.9.0/2.9beta0 (svn:24165)) by Vyacheslav
> Frolov on Unix Linux (2.6.32-279.19.1.el6.x86_64-x86_64)
>
> Asterisk 11.1.0
> Hylafax 6.0.6
>
>
> Thanx in advance and greetings,
> Carsten.
>
>
> [1] Yes, I know: the Berofix appliance can talk directly to the
> t38modems, which works perfectly well here. But there is a limitation of
> 140 SIP Accounts in the Berofix and we have to serve ~500 fax numbers.
> So we had to set Asterisk between the Berofix and the t38modems, bearing
> the SIP accounts.
>
>