DTMF

VHF Signalling system usually used for sending the required digits to be dialled on a telephone system. The two decode windows are an accurate analysis and decode of the parameters of the Selcal signal sequence as follows.

The tone system is as follows:

 

 

1208

1336

1477

1633

697

1

2

3

A

770

4

5

6

B

852

7

8

9

C

941

*

0

#

D