Konica Minolta 7416MFG Advanced Information page 258

Miscellaneous
Term
Touch-tone signals
7416MFG
Definition
A signal used on the telephone line; used when calling on a
push-button line or using push-button services.
By pressing the [ ] key in the 10-Key Pad, touch-tone signals
are used, even if a dial phone line is connected.
9
9-11