fax for asterisk not working over IAX trunk

[icomedias]

I've been successfully using fax for asterisk on my asterisk*now installation for quite some time. PSTN Connectifity used to be a SIP trunk [on a dedicated IP line]; Faxing worked OK.
Now, we switched to an IAX trunk, also on a dedicated IP line and faxing completely stoped working.

When calling the fax extension via SIP (trunk or extension) I can hear the "twittering" generated by ReceiveFax application.
Calling the same fax extension via IAX does NOT result in the expected fax sound and results in disconnect after just a couple of seconds.

here's the log with verbose 6 and fax debugging turned on:

Code: Select all

2011-03-01 18:00:10 VERBOSE13546 pbx.c:     -- Executing s@ext-fax:2 NoOp("IAX2/MyIaxTrunk-257", "Receiving Fax for: myemail@example.com , From: "private" <00000000000000>") in new stack
2011-03-01 18:00:10 VERBOSE13546 pbx.c:     -- Executing s@ext-fax:3 StopPlayTones("IAX2/MyIaxTrunk-257", "") in new stack
2011-03-01 18:00:10 VERBOSE13546 pbx.c:     -- Executing s@ext-fax:4 ReceiveFAX("IAX2/MyIaxTrunk-257", "/var/spool/asterisk/fax/1298998809.13.tif") in new stack
2011-03-01 18:00:10 VERBOSE13546 res_fax.c:     -- Channel 'IAX2/MyIaxTrunk-257' receiving FAX '/var/spool/asterisk/fax/1298998809.13.tif'
2011-03-01 18:00:10 VERBOSE13546 res_fax_digium.c:     -- Channel 'IAX2/MyIaxTrunk-257' FAX session '1' started
2011-03-01 18:00:10 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  000.000314 , STAT_EVT_STRT_RX       st: IDLE         rt: IDLENSRX
2011-03-01 18:00:10 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  000.000640 , STAT_EVT_RX_HW_RDY     st: WT_RX_HW_RDY rt: RRDYNHRY
2011-03-01 18:00:10 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  000.000853 , P30EVN_RECEIVE_STARTED
2011-03-01 18:00:10 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  000.001042 , STAT_INFO_CSI
2011-03-01 18:00:10 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  000.001260 , STAT_INFO_DIS
2011-03-01 18:00:10 VERBOSE13546 res_fax.c:        > Channel 'IAX2/MyIaxTrunk-257' fax session '1',  000.094646 , stack sent 5 frames (100 ms) of energy.
2011-03-01 18:00:10 VERBOSE13546 res_fax.c:        > Channel 'IAX2/MyIaxTrunk-257' fax session '1',  000.153923 , stack sent 3 frames (60 ms) of silence.
2011-03-01 18:00:13 VERBOSE13546 res_fax.c:        > Channel 'IAX2/MyIaxTrunk-257' fax session '1',  003.154785 , stack sent 150 frames (3000 ms) of energy.
2011-03-01 18:00:13 VERBOSE13546 res_fax.c:        > Channel 'IAX2/MyIaxTrunk-257' fax session '1',  003.214706 , stack sent 3 frames (60 ms) of silence.
2011-03-01 18:00:14 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  004.153138 , STAT_EVT_TMR_INT_EXP   st: WT_DIS_RSP   rt: XXXXNTIX
2011-03-01 18:00:15 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  005.244921 , STAT_EVT_TX_V21_DONE   st: WT_HW_CLS    rt: UNEXPECT
2011-03-01 18:00:16 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  006.654069 , STAT_EVT_HW_CLOSE      st: WT_HW_CLS    rt: WCLSNCLS
2011-03-01 18:00:16 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  006.654188 , STAT_SES_COMPLETE
2011-03-01 18:00:16 VERBOSE13548 res_fax_digium.c:     -- FAX handle 0:  006.654231 , P30EVN_COMPLETE
2011-03-01 18:00:24 ERROR13546 res_fax.c: channel 'IAX2/MyIaxTrunk-257' FAX session '1' failure, reason: 'fax session timed-out' (TIMEOUT)


I'd be really grateful for any hint what'S going on - have I overlooked something?

[icomedias]

Turns out Fax for Asterisk had nothing to do with the problem: our IAX provider hangs up incomming calls unless Ringing() is signaled before Answering the call. Adding that to the dialplan for my Fax extension fixed the issue.