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Fax from ATA not detected


I've a customer with CCM 4.1 and several ata; almost all fax are working fine exept when they must be intercepted as fax call.

I'll try to be more clear;

In some place there are "devices" that collect both voice and data call from fax connected to ata. If the call is voice is sent to a phone, if the call is data is sent to an analog fax machine.

What we see is that data calls are not correctly forwarded. I've seen where it's explained FAX-PASSTHROUGHT are sent as voice call... could be this the trouble ? I've to force fax as FAX MODE ?

Any suggest ?

Many thanks


Hall of Fame Super Red

Re: Fax from ATA not detected

Hi Luigi,

Have a look at the following;

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator's Guide (SCCP) (, Rev B0)

Configuring and Debugging Fax Services

Configuring and Troubleshooting the Cisco ATA 186 with Fax

Configure Fax Detection Method on the Cisco ATA 186

Use a web browser and go to http:///dev (for example, in order to configure the Cisco ATA 186 using the web interface.

You must configure these parameters in order to configure the Cisco ATA 186.

Audio Mode

bit 2 (18)=0 Enable detection of FAX CED (answer) tone and switch to FAX mode for the rest of the call if the tone is detected.

Hope this helps!


Community Member

Re: Fax from ATA not detected


I'll try the links You sent me, but my problem is not Fax not detected from fax-machine connected to ata;

My issue is fax not detected when sent from ata.

I'll let You know

many thanks and regards


Community Member

Re: Fax from ATA not detected

Any luck with this? I'm about to take on the ATA vs. Fax battle myself.



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