Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

IP Telephony: ATA 186 fail faxing sip provider SoftX3000 Huawei

Hi, my scenary it cucm7.1 - h323 CUBE gateway - SIP TRUNK

i have connected ata 186,the fax fail becouse cisco try to make in passthru but the sip provider SoftX3000 Huawei switch to t38 mode in the invite.

and the ATA cannot work with T38 fax relay.

038350: *Oct 31 21:41:51.662: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg:


INVITE sip:53197010@ SIP/2.0

Record-Route: <sip:;ftag=3d60a040;lr=on>

Via: SIP/2.0/UDP;branch=z9hG4bK04f3.0577.0

Via: SIP/2.0/UDP;branch=z9hG4bKa42133860

Call-ID: FC2BC06C-C59C11DE-9A52A3B6-D1A93BB0@

From: <sip:3548140@>;tag=3d60a040

To: <sip:53197010@>;tag=3F2B9540-1C6A


Contact: <sip:>

Max-Forwards: 69

Content-Length: 451

Content-Type: application/sdp


o=HuaweiSoftX3000 6934792 6934794 IN IP4

s=Sip Call

c=IN IP4

t=0 0

m=image 61610 udptl t38





m=audio 61712 RTP/AVP 8 0 101

a=rtpmap:8 PCMA/8000

a=rtpmap:0 PCMU/8000

a=rtpmap:101 telephone-event/8000


a=silenceSupp:off - - - -

a=ecan:fb on -


a=fmtp:101 0-15


038351: *Oct 31 21:41:51.662: //-1/xxxxxxxxxxxx/SIP/Info/ccsip_new_msg_preprocessor: Checking Invite Dialog

038491: *Oct 31 21:41:51.670: H245 MSC OUTGOING PDU ::=

value MultimediaSystemControlMessage ::= request : requestMode :


sequenceNumber 1




type audioMode : g711Ulaw64k : NULL




038498: *Oct 31 21:41:51.674:

038499: *Oct 31 21:41:51.674: H245 MSC INCOMING PDU ::=

value MultimediaSystemControlMessage ::= response : requestModeReject :


sequenceNumber 1

cause requestDenied : NULL



I was investigating about the issue...the ata 186 can work with these fax modes:

• G.711 fax pass-through

• G.711 fax mode

And the sip provider's SoftX3000 Huawei support these fax modes:

Facsimile codec mode

T.38 mode:

Media gateway encodes facsimile signals from a facsimile machine according to the

encoding mode recommended in the T.38 protocol, and encapsulates them in IFP data

packets which will be transmitted in real time on the IP network. The transmission of IFP

data packets is based on either TCP or UDP. In the case of TCP, the TCP provides a

mechanism to guarantee the reliability of the transmission by itself. In the case of UDP,

the T.38 protocol provides a forward error mechanism. Therefore, an outstanding

advantage of the T.38 mode is its high reliability which ensures a high quality of facsimile.

Normal mode

Media gateway encodes facsimile signals sent by a facsimile machine to be voice

codes (such as G.711, G.723, or G.729), and encapsulates them in RTP data packets

which will be transmitted in real time on the IP network. Because the transmission of

RTP data packets is based on UDP only which does not provide a forward error

correction mechanism, facsimile communication in such a normal mode is sensitive to

loss of packets. Once some packets are lost during the transmission, the video at the

receiver may be incomplete or the facsimile may be interrupted. Operation Manual-Configuration Guide.pdf


So the ata 186 g.711 fax mode its in huawei the normal fax mode, in that case it should be works...

What i have to tell to the provider ???

what its your opinion about the fax mode cisco/huawei ?

any help about the issue ...


Re: IP Telephony: ATA 186 fail faxing sip provider SoftX3000 Hua

Hi  Andresfmg,

Can you please post the h323 configuration. Am testing the same scenari, so that i can use is as a referrence.

I faced some issues with Unity. Once the call is transfered to the Mailbox, am not able to hear any welcome message from Unity.