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Analog modem on ATAs

PostPosted: 09/06/2015, 18:25
by daniele.longo@starsystem.biz
Recently it faced to me a curious problem.
A customer has the need to connect two analog modems connected to the same PBX via fxs gateways.
Codec is foced to ALAW so it won't disturb analog modulation.
BTW, what happens is that:

-- Executing [191@users:1] NoOp("SIP/160-0000230c", "Dialing from 160 to number 191 ")
-- Executing [191@users:1] NoOp("SIP/160-0000230c", "Set callclass to 1")
-- Executing [191@users:1] NoOp("SIP/160-0000230c", "Dst features for active calltype internal:
-- DND:0 MEXT:0 BCF:0 UCF:0 SMSMCN:0 FCF:0 EMAILMCN:1 TOUT:0 CW:1 RING:0 MOBCONFIRMATION:1 ")
-- Executing [191@users:1] NoOp("SIP/160-0000230c", "Device SIP/191 devstate is NOT_INUSE")
-- Executing [191@users:1] NoOp("SIP/160-0000230c", "Calltype internal")
-- Executing [191@users:1] Dial("SIP/160-0000230c", "SIP/191,65,zb(predial^internalcall^1(, http://127.0.0.1/Ring1.wav;info=internal>,4))")
== Using SIP VIDEO CoS mark 6
== Using SIP RTP CoS mark 5
-- SIP/191-0000230d Internal Gosub(predial,internalcall,1(,<http://127.0.0.1/Ring1.wav;info=internal>,4)) start
-- Called SIP/191
== Extension Changed 160[users] new state InUse for Publishing User '160'
-- SIP/191-0000230d is ringing
== Extension Changed 191[users] new state Ringing for Publishing User '191'
== Extension Changed 191[users] new state InUse for Publishing User '191'
-- SIP/191-0000230d answered SIP/160-0000230c
== Extension Changed 191[users] new state InUse for Publishing User '191'
== Extension Changed 160[users] new state InUse for Publishing User '160'
-- Locally bridging SIP/160-0000230c and SIP/191-0000230d
== Extension Changed 160[users] new state InUse for Publishing User '160'
== Extension Changed 191[users] new state InUse for Publishing User '191'
-- Locally bridging SIP/160-0000230c and SIP/191-0000230d
[Jun 9 17:48:01] WARNING[3902][C-0000138d]: chan_sip.c:8623 initialize_udptl: Disabling T38 for dialog.
[Jun 9 17:48:01] WARNING[3902][C-0000138d]: chan_sip.c:11599 process_sdp: Failed to initialize UDPTL, declining image stream
[Jun 9 17:48:01] WARNING[3902][C-0000138d]: chan_sip.c:11784 process_sdp: Failing due to no acceptable offer found
[Jun 9 17:48:01] WARNING[3902][C-0000138d]: chan_sip.c:13573 __transmit_response: Send response to peer 191 to incoming request INVITE: '488 Not acceptable here'; From: <sip:191@10.135.0.1>;tag=7e3dbf79; To: "ATA_06" <sip:160@10.135.0.1>;tag=as5143441a; callid - '181f37f506ba29097342c27d0a0a8222@127.0.0.1:6050'. Reason cause: 16 (Normal Clearing)
== Extension Changed 160[users] new state InUse for Publishing User '160'
[Jun 9 17:48:02] WARNING[3902][C-0000138d]: chan_sip.c:31974 handle_request_bye: Got request BYE from peer 191; From: <sip:191@10.135.0.1>;tag=7e3dbf79; To: "ATA_06" <sip:160@10.135.0.1>;tag=as5143441a; callid - '181f37f506ba29097342c27d0a0a8222@127.0.0.1:6050'. Reason cause: 16 (Normal Clearing)
-- SIP/160-0000230c Internal Gosub(hdlr,internal,1) start
== Extension Changed 191[users] new state Idle for Publishing User '191'
== Extension Changed 191[users] new state Idle for Publishing User '191' (queued)
== Spawn extension (users, 191, 1) exited non-zero on 'SIP/160-0000230c'
== Extension Changed 160[users] new state Idle for Publishing User '160'
[Jun 9 17:48:02] WARNING[11766][C-0000138d]: chan_sip.c:18685 transmit_request_with_auth: Send request BYE to peer 160; From: <sip:191@10.135.0.1>;tag=as203d0f86; To: "160" <sip:160@10.135.0.1>;tag=085082dc; callid - '0af9f0ef1f38e08a4f1d94091ee20373@10.135.0.106'. Reason cause: 16 (Normal Clearing)
== Extension Changed 160[users] new state Idle for Publishing User '160'



Why it tries to initialize an image stream? Some sort of FAX autodetect happens? Is it it possible to deactivate that function?

Tested on: WMS 3.80.29199.22, gateway Wildix w01fxsr2 fw 3.14

P.S. After that, gateways stay hanged ( unavailable/busy ) until reboot.

Re: Analog modem on ATAs

PostPosted: 10/06/2015, 11:37
by matteo.erba
Hello Daniele,
I'm sorry but the modem connection over our analog gateways is not supported yet

Re: Analog modem on ATAs

PostPosted: 25/06/2015, 12:58
by daniele.longo@starsystem.biz
Even disabling on the media gateways T38, echo canceller and silence suppression, and forcing use of alaw codec, the modem modilation still doesn't work.
Seems like some sort of noise reduction is still active.

BTW, :idea: in the end this problem was solved changing a bit the connection strategy, using an IP to RS485 converter and reconfiguring both ends to not use modems anymore.