Due to popular demand, I will try to explain how to disable/enable T.38 support on the Fritz!Box. Unfortunately the setting for T.38 support is a global settings, so you cannot activate/deactivate T.38 support per SIP account, however careful routing should cope with this limitation. So this is the way to go:
- Choose Settings / Einstellungen from the top menu
- Select Advanced Settings / Erweiterte Einstellungen from the left menu
- Go to Telephony / Telefonie
- Click Internet Telephony / Internettelefonie
- Select the Advanced Settings / Erweiterte Einstellungen Tab
- Goto to the bottom of the page and (un-)tick the box Fax transmission also with T.38 / Fax transmission also with T.38
Happy faxing!