[asterisk-users] fax tone testing

Kevin P. Fleming kpfleming at digium.com
Tue Apr 3 17:04:34 CDT 2012

On 04/02/2012 03:18 AM, Anita Hall wrote:
> Hi
> I suspect that my telco set-up is acting funny and I want to use
> spectral analysis to confirm the culprit :)
> What is the best way to generate Fax tones from a dialplan and then
> record them at the other end? Also, where can I get a list of the all
> the tones and duration which are used in Fax.

There are two primary tones used during FAX transaction setup: CNG and 
CED. Everything else used is modem signaling, which while technically is 
composed of tones, can't be simulated using a simple tone generator.

The PlayTones() dialplan application in Asterisk can be used to generate 
these tones.

Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org

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