My 3CX fax server does not initiate handshake when receiving a call from an Anonymous caller (caller ID blocked).
I have several DIDs pointing to different extensions for faxing purposes.
So for example I have 16173998217 set to “Send fax to” “email of extension 221 Corey Boyle”
This works great as long as the incoming fax is sent from a line that does not have caller ID blocked.
If the caller ID is blocked, the fax server answers the line, but never gives tones.
I can confirm this with my iPhone by switching “show my caller ID” on and off.
If I call with “show my caller ID” set to “on” I hear the tones.
If I call with “show my caller ID” set to “off” I do not hear the tones.
Any help would be appreciated, as this causes quite an issue for me and my users. A surprising number of faxes are sent from lines with caller ID blocked.
I have attached a portion of my server log.
You can see an anonymous call at 09:57:15.266 and a normal call at 09:57:48.534.
I have several DIDs pointing to different extensions for faxing purposes.
So for example I have 16173998217 set to “Send fax to” “email of extension 221 Corey Boyle”
This works great as long as the incoming fax is sent from a line that does not have caller ID blocked.
If the caller ID is blocked, the fax server answers the line, but never gives tones.
I can confirm this with my iPhone by switching “show my caller ID” on and off.
If I call with “show my caller ID” set to “on” I hear the tones.
If I call with “show my caller ID” set to “off” I do not hear the tones.
Any help would be appreciated, as this causes quite an issue for me and my users. A surprising number of faxes are sent from lines with caller ID blocked.
I have attached a portion of my server log.
You can see an anonymous call at 09:57:15.266 and a normal call at 09:57:48.534.
Phone System 