Voice API for Windows Operating Systems Library Reference — November 2003 539
6
6.Supplementary Reference
Information
This chapter provides reference information on the following topics:
•DTMF and MF Tone Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
•DTMF and MF Detection Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540

6.1 DTMF and MF Tone Specifications

Table 27 provides information on DTMF specifications. Table 28 provides information on MF tone
specifications.
Table 27. DTMF Tone Specifications
Code Tone Pair
Frequencies (Hz)
Default Length
(msec)
1 697, 1209 100
2 697, 1336 100
3 697, 1477 100
4 770, 1209 100
5 770, 1336 100
6 770, 1477 100
7 852, 1209 100
8 852, 1336 100
9 852, 1477 100
0 941, 1336 100
* 941, 1209 100
# 941, 1477 100
a 697, 1633 100
b 770, 1633 100
c 852, 1633 100
d 941, 1633 100