Phone numbers/ DTMF

What are the frequencies for DTMF (Dual-tone multi-frequency) digits?

           1209 Hz   1336 Hz   1477 Hz   1633 Hz

 697 Hz       1        2         3         F0/A
 770 Hz       4        5         6         F/B
 852 Hz       7        8         9         I/C
 941 Hz       *        0         #         P/D

The right hand column (obviously) is not normally available but has certain applications. The functions are labelled either F0, F, I, P or A, B, C, D.

How can I identify a 'phone number from a recording of the DTMF digits?

IF you have Star services (it works on system X)

• dial the number, hangup
• dial *52# you'll hear "telephone number 123456 is stored"
• *54# will dial this number

This is an undocumented feature that has been around for at least 4 years.

[end of uk.telecom FAQ part 3/3]