ATA and FAX Machines

Unanswered Question

Hi, We've a lot of problem with FAX machines connected to ATA devices. When the fax machines place a call (off-hook) to a external line (FXO connected to a PSTN) and then end (on-hook) it not release the call blocking the ATA and FXO, with supervisory disconnect configured in FXO solve the problem partially because in certain scenarios the lines connected not send dual tones.

Can help us, and tell why the ATA not release the call when the Fax machines goes on-hook?..

Call Manager 4.1(3)sr5b

ATA 186 SCCP11.8-2-2SR1S

C2851 IOS 12.4(12)

Thanks in advance,

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Jon Nelson Tue, 10/23/2007 - 17:20
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I would recommend moving to an H323 image on the ATA's if you are going to use them for faxing. This seems to eliminate a lot of the issues with faxing on the ATA's. You can also move to an FXS port in the router as an alternative.

Thank you,


paolo bevilacqua Tue, 10/23/2007 - 17:26
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Jon was just faster than me in saying these two exact things... Good luck!

Mr Sanchez,

The ATA 186 does not support T.38 fax realy, which is the protocol that should be used to make fax communication reliable over IP networks. I suggest you look into connecting your fax machines with an ATA that will support T.38 and setup your environment to transport T.38 over IP to your PSTN gateways. Products to look for Sagem Easy ATA.

Thanks to all for yours fast answers, let me tell first that the problem is in voice call too and we disable fax t.38 and modem passthrough in gateways for fax call, its appears like ATA is not know when the fax machine goes on-hook, we've Cordless Phone and it's seems to work fine. In other hand, if we move ATA to H.323 we believe that maybe could lost Call Pickup group, Hunt Group, it's correct?

paolo bevilacqua Wed, 10/24/2007 - 06:23
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the firmware you have mentioned is not for ata, it's for a 7911.

Please verify that you have ATA030203SCCP051201A.ZUP as "load" for the ATA.

And yes, switching to H.323 would make you loose the ability to access service via FAC.

danaronson Wed, 10/24/2007 - 10:08
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Analog fax (T.30) is tricky at best. You might consider using a T.38 fax server software solution that could utilize your gateway(s) to send and receive faxes via IP to the gateway (as opposed to an analog codec) eliminating the need for ATA's altogether. I would be happy to provide additional information if needed.

paolo bevilacqua Thu, 10/25/2007 - 07:54
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Apparently all goes well but the ATA doesn't disconnects properly, seems a solvable problem.

Have you checked all the lines setting in the web or config file ?

All failing the problem should be give to the TAC. An FXS port must disconnect in any case, when the device goes on-hook.

danaronson Fri, 10/26/2007 - 09:48
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Do you have MFD's with scan-to-email? You can use those to funnel faxes to an XMediusFAX server. This is a pure IP solution that woudl allow you to eliminate ATA's altogether. This also gives you an audit trail on all documents in and out of your organization. Plus, all documents can be archived or deleted based on regulatory need or internal policies (i.e. 30 days, 3 years, forever, etc.)


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