FAX detection

[kikpal]

How Pbx detect a line if it is a fax or a normal call
If it is a fax forward it to the fax server with both numbers the incoming and the number of the person is beeing called (PBX Number) if not let it throe as if there is no fax detection

[Dave_DUP]

The voice mailbox identifies that the call is a fax by detecting the fax tone during the first twelve seconds and transfers it to the fax number.

Hope this answers your question

[kikpal]

How can I do that in 4400 system?

[Dave_DUP]

The FAX option is turned on in the 4635 and then set up by the user at the set. The user will get a message "You have the FAX opion on your voicemail" It will walk them through the set up. I have been looking for the setup on this in the voicemail docs but have not located it. I only set this up once about 2 years ago so I don't remember.

[vad]

You cannot recognize incoming FAX calls before answer.
If incoming TG - ISDN type - in setup message may be IE:[04] BEARER CAPABILITY (l=3) 90 90 a2.
A value of 90 would likely, but not always,correspond to a fax.
In any other case you can recognize FAX after answering (calling or called fax will send calling or answering tone).
CNG (Calling Tone) indicates that the calling device is a non-speech terminal. The format for the
CNG signal is an 1100 Hz ± 38 Hz tone which is on for 0.5 seconds ± 15%, then off for 3.0
seconds ± 15%. This signal is mandatory for automatic calling units and optional for manual units.
As a point of practical reference, this signal is used to identify an incoming fax call by automatic
devices which switch a single phone line between voice and fax terminals.
CED (Called Tone) indicates that the answering device is a non-speech terminal. An automatic
answering fax device sends a CED (2100 Hz ±15 Hz answer tone) starting 1.8 to 2.5 seconds after
it answers a call. CED should last 2.6 to 4 seconds. For best international compatibility, the CED
should be 3 seconds in duration.