Hi All, We are having trouble setting up a fax system with 3cx. One of our customers got switched to all ip. (Provider: Telekom, Package: DeutschlandLAN IP Voice/Data S Premium) The complete setup is as following: Modem: Digitalisierungsbox Smart Firewall with PPPoE connection: Watchguard T30, Ports are forwared - Firewall check is fine 3CX Version: 15.5 ISDN Gateway: Patton SmartNode 4112 Fax System: MFP Canon iRC3080i The fax number is logged in as a SIP-Trunk to the provider. The patton is configured as FXS gateway and provisioned by the 3cx. (Local Subnet, Fax Transmission Mode: Fax in Audio G711A(if provider does not support T.38), Fax Extension is added as first Extension) Connecting a phone to the gateway works. I can do and receive calls on it. When I try to send a fax, it calls the remote station but immediately stops and ends the call when the remote station takes the call. We have changed the fax system with no success. We tried to use a software fax (T.38 Printer) without success. I'd hope that someone has faced similiar problems and can help me with this.