[Asterisk-Users] Problem with fax tone (CNG) from TxFax and busy detect

[Eric Wieling]

Michael Welter wrote:

> Using the "|caller" parameter, TxFax injects the fax tone (CNG) onto the 
> line.  With the CNG tone, asterisk is unable to detect the busy tones.
> 
> If I were to remove "|caller" then the receiving station wouldn't 
> receive the CNG tone and possibly not direct the call to the fax machine.
> 
> Is there a way for * to detect busy tones while ignoring (filtering) the 
> fax tones?

There might be a way to patch asterisk to do this, but currently the 
only way that I know of is to use a PRI or other type of line that 
provides busy/answer/etc indications.