MF R1 signaling

MF Stands for multi frequency

Line frequency 2600 Hz

Frequencies     900    1
(Hz)
               1100    2     3

               1300    4     5     6

               1500    7     8     9     0

               1700   ST1   ST2   KP    ST3   ST

                      700   900  1100  1300  1500

                      Frequencies (Hz)