How to design fax transmission through ATA 187

[Fikri FIRAT]

Hi all,

We wish to implement ATA 187 devices to take care of fax transmission. In the CUCM 8.6.2 , I configured the device as follows :

Web Access  : Enabled

Auto Barge : Enabled

CDP : Enabled

Fax Mode : T.38 Fax Relay

Fax Error Correction Mode Override : Off

Maximum Fax Rate : 14400bps

Impedance : 600 ohms complex

Input Audio Level : NoDbPadding

Output Audip Level : NoDbPadding

Caller Connect Polarity : User forward polarity

Caller Disconnect Polarity : User forward polarity

Callee Connect Polarity : User forward polarity

Callee Disconnect Polarity : User forward polarity

Caller ID : Bellcore FSK

Call Sequence : Bellcore FSK

Reorder Delay : 0

Mute progress Tone : Disabled

The Line is OK, makes phone calls, but does not send / receive fax.

I'm new to the ATA device, the bottom line is how to design fax transmission using ATA 187 devices over T.38 and CUCM v8.6.2

Thanks in advance,

Regards

[Harmit Singh]

Hi Fikri,

Can you provide the exact call flow please? What protocol are you using on your ingress / egress voice gateway? Is the ATA at a remote location? Are you running the latest ATA firmware? Can you attach the running config of the ingress/egress voice gateway?

Regards,

Harmit.

[Fikri FIRAT]

Hi Harmit,

ATA is in a lab environment, so currently is not at a remote location only the fax device is connected to the ATA, and it should send/receive fax through T.38, currently there are no configs on the voice gateway regarding fax transmission, the design will be from scratch, ATA load id : APP187.9-2-1-0

[Harmit Singh]

Hi Fikri,

Just to add to my previous message, here is a typical call flow where ATA 187 can be used along with the VG config:

Telco – PRI – GW – MGCP – CUCM – SIP – ATA187 – Fax/Modem [Can do both Passthrough and T38]

Config for GW doing Modem Passthrough:

no ccm-manager fax protocol cisco                              
mgcp modem passthrough voip mode nse 
mgcp modem passthrough voip codec g711ulaw

Config for GW doing T38:

no ccm-manager fax protocol cisco               
no mgcp fax t38 inhibit  
mgcp package-capability fxr-package
mgcp default-package fxr-package
no mgcp fax t38 ecm
mgcp fax t38 nsf 000000

HTH.

Regards,

Harmit.

[Fikri FIRAT]

Hi, thanks for your quick replies!

We currently use SIP instead of MGCP

[Harmit Singh · Accepted solution]

Hi Fikri,

In case of SIP, you can apply the following config on your VG:

! Fax configuration for Inbound / Outbound VoIP dial-peer

dial-peer voice voip

  fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback pass-through

  fax-relay ecm disable

  fax nsf 000000

  fax-relay sg3-to-g3

HTH.

Regards,

Harmit.

[Fikri FIRAT]

Hi Harmit,

We did the following configuration as you guided but the transmission is still not okay

dial-peer voice 76 voip

translation-profile outgoing FAX

huntstop

destination-pattern 888883006

session protocol sipv2

session target ipv4:10.231.103.101

session transport udp

voice-class codec 99 

fax-relay ecm disable

fax protocol t38 version 0 ls-redundancy 2 hs-redundancy 0 fallback none

[Harmit Singh]

Hi Fikri,

Did you try an incoming fax or outgoing? The dialpeer is an outgoing dialpeer. Is that the CUCM IP address: 10.231.103.101? So your callflow should be:

Telco – PRI – GW – SIP – CUCM – SIP – ATA187 – Fax

Is the above correct? Did you upgrade to the latest firmware on the ATA? Kindly capture the following:

++     Can you take packet captures from the ATA and the voice gateway by spanning the switchports where they are connected?

++     Detailed CUCM SDI and SDl traces from all nodes in the cluster

++     Screenshot of the ATA config page as well as the SIP trunk config page on CUCM.

++     The following debugs from the VG:

debug voip ccapi inout

debug ccsip messages

debug voip vtsp all

debug isdn q931

Collecting debugs in Router logging buffer

------------------------------------------

Router#configuration terminal

Router(config)#no logging console

Router(config)#service timestamps debug datetime msec

Router(config)#logging buffered debugging

Router(config)#service sequence

Router(config)#no logging rate-limit

Router(config)#exit

Router#

Please capture the above for one call along with the calling, called party numbers, timestamp and symptom observed. Apologies for the amount of data required but it is necessary to troubleshoot. :-)

Regards,

Harmit.

[Fikri FIRAT]

Hi Harmit,

After applying the correct config and upgrading to the firmware 9.2.3.1, which is the latest release, we can send and receive fax through T.38, everything works fine, thank you for your guidance and support!

Regards,

Fikri

[Harmit Singh]

Hi Fikri,

Excellent news! Glad to hear that! Could you please mark this discussion as answered to help others who refer to it as well? Appreciate it. Happy New Year!

Regards,

Harmit.

[Risat]

Can you please share the corrections that you made to fix this issue or kindlyshare the working config from the VG.