TA Triumph-Adler P-3525 MFP - Manual (Page 66)

FAX Operation (Advanced)
4-12
Using the Remote Switch Dial
To start fax reception by operation from the connected telephone set, use the following operation.
1 The connected telephone set makes a ringing tone.
2 Lift the handset of the telephone.
3 When you hear the fax tone from the handset, enter the
two-digit remote switch dial number using the dial button
on the telephone set.
NOTE: The remote switch dial is set to 55 at the factory.
4 The telephone line switches to the machine, and
reception starts.